Meaning of the Word 'Caliph'
The word 'Caliph' is the English form of the Arabic word 'Khalifa,' which is short for Khalifatu Rasulil-lah. The latter expression means Successor to the Messenger of God, the Holy Prophet Muhammad (peace be on him). The title 'Khalifatu Rasulil-lah'. was first used for Abu Bakr, who was elected head of the Muslim community after the death of the Prophet.
The Significance of the Caliphate
The mission of Prophet Muhammad (peace be on him), like that of the earlier messengers of God, was to call people to the worship of and submission to the One True God. In practice, submission to God means to obey His injunctions as given in the Holy Qur'an and as exemplified by Sunnah (the practice of the Prophet). As successor to the Prophet, the Caliph was the head of the Muslim community and his primary responsibility was to continue in the path of the Prophet. Since religion was perfected and the door of Divine revelation was closed at the death of the Prophet, the Caliph was to make all laws in accordance with the Qur'an and the Sunnah. He was a ruler over Muslims but not their sovereign since sovereignty belongs to God alone. He was to be obeyed as long as he obeyed God. He was responsible for creating and maintaining conditions under which it would be easy for Muslims to live according to Islamic principles, and to see that justice was done to all. Abu Bakr, at the time he accepted the caliphate, stated his position thus:
"The weak among you shall be strong with me until their rights have been vindicated; and the strong among you shall he weak with me until, if the Lord wills, I have taken what is due from them... Obey me as long as I obey God and His Messenger. When I disobey Him and His Prophet, then obey me not."
The Rightly-Guided Caliphs (Al-Khulafa-ur-Rashidun)
Those Caliphs who truly followed in the Prophet's foot steps are called 'The Rightly-Guided Caliphs' (Al-Khulafa-ur Rashidun in Arabic). They are the first four Caliphs: Abu Bakr, 'Umar, Uthman and Ali. All four were among thc earliest and closest Companions of the Prophet (peace be on him). They lived simple and righteous lives and strove hard for the religion of God. Their justice was impartial, their treatment of others was kind and merciful, and they were one with the people - the first among equals. After these four, the later Caliphs assumed the manners of kings and emperors and the true spirit of equality of ruler and ruled diminished to a considerable extent in the political life of Muslims.
It should be clearly understood that the mission of Prophet Muhammad (peace be on him), and hence that of the Rightly-Guided Caliphs, was not political, social or economic reform, although such reforms were a logical consequence of the success of this mission, nor the unity of a nation and the establishment of an empire, although the nation did unite and vast areas came under one administration, nor the spread of a civilization or culture, although many civilizations and cultures developed, but only to deliver the message of God to all the peoples of the world and to invite them to submit to Him, while being the foremost among those who submitted.
What About the Present?
The primary responsibility of an Islamic government is still the same as it was in the days of the early Caliphs: to make all laws in accordance with the Qur'an and the Sunnah, to make positive efforts to create and maintain conditions under which it will be possible and easy for Muslims to live an Islamic life, to secure impartial and speedy justice for all, and to strive hard in the path of God. Any government which is committed to such a policy is truly following the message delivered by the Prophet (peace be on him).
The First Caliph, Abu Bakr (632-634 A.C.)
"If I were to take a friend other than my Lord, I would take Abu Bakr as a friend." (Hadith)
Election to the Caliphate
The Prophet's closest Companion, Abu Bakr, was not present when the Holy Prophet (peace be on him) breathed his last in the apartment of his beloved wife of later years, Aisha, Abu Bakr's daughter. When he came to know of the Prophet's passing, Abu Bakr hurried to the house of sorrow.
"How blessed was your life and how beatific is your death,"
he whispered as he kissed the cheek of his beloved friend and master who now was no more.
When Abu Bakr came out of the Prophet's apartment and broke the news, disbelief and dismay gripped the community of Muslims in Medina. Muhammad (peace be on him) had been the leader, the guide and the bearer of Divine revelation through whom they had been brought from idolatry and barbarism into the way of God. How could he die? Even Umar, one of the bravest and strongest of the Prophet's Companions, lost his composure and drew his sword and threatened to kill anyone who said that the Prophet was dead. Abu Bakr gently pushed him aside, ascended the steps of the lectern in the mosque and addressed the people, saying
"O people, verily whoever worshipped Muhammad, behold! Muhammad is indeed dead. But whoever worships God, behold! God is alive and will never die."
And then he concluded with a verse from the Qur'an:
"And Muhammad is but a Messenger. Many Messengers have gone before him; if then he dies or is killed, will you turn back upon your heels?" [3:144]
On hearing these words, the people were consoled. Despondency gave place to confidence and tranquility. This critical moment had passed. But the Muslim community was now faced with an extremely serious problem: that of choosing a leader. After some discussion among the Companions of the Prophet who had assembled in order to select a leader, it became apparent that no one was better suited for this responsibility than Abu Bakr. A portion of the speech the First Caliph gave after his election has already been quoted in the introduction.
Abu Bakr's Life
Abu Bakr ('The Owner of Camels') was not his real name. He acquired this name later in life because of his great interest in raising camels. His real name was Abdul Ka'aba ('Slave of Ka'aba'), which Muhammad (peace be on him) later changed to Abdullah ('Slave of God'). The Prophet also gave him the title of 'Siddiq' - 'The Testifier to the Truth.'
Abu Bakr was a fairly wealthy merchant, and before he embraced Islam, was a respected citizen of Mecca. He was three years younger than Muhammad (peace be on him) and some natural affinity drew them together from earliest child hood. He remained the closest Companion of the Prophet all through the Prophet's life. When Muhammad first invited his closest friends and relatives to Islam, Abu Bakr was among the earliest to accept it. He also persuaded Uthman and Bilal to accept Islam. In the early days of the Prophet's mission, when the handful of Muslims were subjected to relentless persecution and torture, Abu Bakr bore his full share of hardship. Finally when God's permission came to emigrate from Mecca, he was the one chosen by the Prophet to accompany him on the dangerous journey to Medina. In the numerous battles which took place during the life of the Prophet, Abu Bakr was always by his side. Once, he brought all his belongings to the Prophet, who was raising money for the defense of Medina. The Prophet asked "Abu Bakr, what did you leave for your family?" The reply came: "God and His Prophet."
Even before Islam, Abu Bakr was known to be a man of upright character and amiable and compassionate nature. All through his life he was sensitive to human suffering and kind to the poor and helpless. Even though he was wealthy, he lived very simply and spent his money for charity, for freeing slaves and for the cause of Islam. He often spent part of the night in supplication and prayer. He shared with his family a cheerful and affectionate home life.
Such, then, was the man upon whom the burden of leadership fell at the most sensitive period in the history of the Muslims.
As the news of the Prophet's death spread, a number of tribes rebelled and refused to pay Zakat (poor-due), saying that this was due only to the Prophet (peace be on him). At the same time a number of impostors claimed that the prophethood had passed to them after Muhammad and they raised the standard of revolt. To add to all this, two powerful empires, the Eastern Roman and the Persian, also threatened the new-born Islamic state at Medina.
Under these circumstances, many Companions of the Prophet, including Umar, advised Abu Bakr to make concessions to the Zakat evaders, at least for a time. The new Caliph disagreed. He insisted that the Divine Law cannot be divided, that there is no distinction between the obligations of Zakat and Salat (prayer), and that any compromise with the injunctions of God would eventually erode the foundations of Islam. Umar and others were quick to realize their error of judgment. The revolting tribes attacked Medina but the Muslims were prepared. Abu Bakr himself led the charge, forcing them to retreat. He then made a relentless war on the false claimants to prophethood, most of whom submitted and again professed lslam.
The threat from the Roman Empire had actually arisen earlier, during the Prophet's lifetime. The Prophet had organized an army under the command of Usama, the son of a freed slave. The army had not gone far when the Prophet had fallen ill so they stopped. After the death of the Prophet the question was raised whether the army should be sent again or should remain for the defence of Medina. Again Abu Bakr showed a firm determination. He said, "I shall send Usama's army on its way as ordered by the Prophet, even if I am left alone."
The final instructions he gave to Usama prescribed a code of conduct in war which remains unsurpassed to this day. Part of his instructions to the Muslim army were:
"Do not be deserters, nor be guilty of disobedience. Do not kill an old man, a woman or a child. Do not injure date palms and do not cut down fruit trees. Do not slaughter any sheep or cows or camels except for food. You will encounter persons who spend their lives in monasteries. Leave them alone and do not molest them."
Khalid bin Waleed had been chosen by the Prophet (peace be on him) on several occasions to lead Muslim armies. A man of supreme courage and a born leader, his military genius came to full flower during the Caliphate of Abu Bakr. Throughout Abu Bakr's reign Khalid led his troops from one victory to another against the attacking Romans.
Another contribution of Abu Bakr to the cause of Islam was the collection and compilation of the verses of the Qur'an.
Abu Bakr died on 21 Jamadi-al Akhir, 13 A.H. (23 August 634 A.C.), at the age of sixty-three, and was buried by the side of the Holy Prophet (peace be on him). His caliphate had been of a mere twenty-seven months duration. In this brief span, however, Abu Bakr had managed, by the Grace of God, to strengthen and consolidate his community and the state, and to secure the Muslims against the perils which had threatened their existence.
The Second Caliph, Umar (634-644 A.C.)
"God has placed truth upon Umar's tongue and heart. (Hadith)"
During his last illness Abu Bakr had conferred with his people, particularly the more eminent among them. After this meeting they chose 'Umar as his successor. 'Umar was born into a respected Quraish family thirteen years after the birth of Muhammad (peace be on him). Umar's family was known for its extensive knowledge of genealogy. When he grew up, 'Umar was proficient in this branch of knowledge as well as in swordsmanship, wrestling and the art of speaking. He also learned to read and write while still a child, a very rare thing in Mecca at that time. 'Umar earned his living as a merchant. His trade took him to many foreign lands and he met all kinds of people. This experience gave him an insight into the affairs and problems of men. 'Umar's personality was dynamic, self-assertive, frank and straight forward. He always spoke whatever was in his mind even if it displeased others.
'Umar was twenty-seven when the Prophet (peace be on him) proclaimed his mission. The ideas Muhammad was preaching enraged him as much as they did the other notables of Mecca. He was just as bitter against anyone accepting Islam as others among the Quraish. When his slave-girl accepted Islam he beat her until he himself was exhausted and told her, "I have stopped because I am tired, not out of pity for you." The story of his embracing Islam is an interesting one. One day, full of anger against the Prophet, he drew his sword and set out to kill him. A friend met him on the way. When 'Umar told him what he planned to do, his friend informed him that 'Umar's own sister, Fatima, and her husband had also accepted Islam. 'Umar went straight to his sister's house where he found her reading from pages of the Qur'an. He fell upon her and beat her mercilessly. Bruised and bleeding, she told her brother, "Umar, you can do what you like, but you cannot turn our hearts away from Islam." These words produced a strange effect upon 'Umar. What was this faith that made even weak women so strong of heart? He asked his sister to show him what she had been reading; he was at once moved to the core by the words of the Qur'an and immediately grasped their truth. He went straight to the house where the Prophet was staying and vowed allegiance to him.
Umar made no secret of his acceptance of Islam. He gathered the Muslims and offered prayers at the Ka'aba. This boldness and devotion of an influential citizen of Mecca raised the morale of the small community of Muslims. Nonetheless 'Umar was also subjected to privations, and when permission for emigration to Medina came, he also left Mecca. The soundness of 'Umar's judgment, his devotion to the Prophet (peace be on him), his outspokenness and uprightness won for him a trust and confidence from the Prophet which was second only to that given to Abu Bakr. The Prophet gave him the title 'Farooq' which means the 'Separator of Truth from False hood.' During the Caliphate of Abu Bakr, 'Umar was his closest assistant and adviser. When Abu Bakr died, all the people of Medina swore allegiance to 'Umar, and on 23 Jamadi-al-Akhir, 13 A.H., he was proclaimed Caliph.
After taking charge of his office, 'Umar spoke to the Muslims of Medina:
"...O people, you have some rights on me which you can always claim. One of your rights is that if anyone of you comes to me with a claim, he should leave satisfied. Another of your rights is that you can demand that I take nothing unjustly from the revenues of the State. You can also demand that... I fortify your frontiers and do not put you into danger. It is also your right that if you go to battle I should look after your families as a father would while you are away. "O people, remain conscious of God, forgive me my faults and help me in my task. Assist me in enforcing what is good and forbidding what is evil. Advise me regarding the obligations that have been imposed upon me by God..."
The most notable feature of 'Umar's caliphate was the vast expansion of Islam. Apart from Arabia, Egypt, Iraq, Palestine and Iran also came under the protection of the Islamic government. But the greatness of 'Umar himself lies in the quality of his rule. He gave a practical meaning to the Qur'anic injunction:
"O you who believe, stand out firmly for justice as witnesses to God, even as against yourselves, or your parents, or your kin, and whether it concerns rich or poor, for God can best protect both." [4:135]
Once a woman brought a claim against the Caliph 'Umar. When 'Umar appeared on trial before the judge, the judge stood up as a sign of respect toward him. 'Umar reprimanded him, saying, "This is the first act of injustice you did to this woman!"
He insisted that his appointed governors live simple lives, keep no guard at their doors and be accessible to the people at all times, and he himself set the example for them. Many times foreign envoys and messengers sent to him by his generals found him resting under a palm tree or praying in the mosque among the people, and it was difficult for them to distinguish which man was the Caliph. He spent many a watchful night going about the streets of Medina to see whether anyone needed help or assistance. The general social and moral tone of the Muslim society at that time is well-illustrated by the words of an Egyptian who was sent to spy on the Muslims during their Egyptian campaign. He reported:
"I have seen a people, every one of whom loves death more than he loves life. They cultivate humility rather than pride. None is given to material ambitions. Their mode of living is simple... Their commander is their equal. They make no distinction between superior and inferior, between master and slave. When the time of prayer approaches, none remains behind..."
'Umar gave his government an administrative structure. Departments of treasury, army and public revenues were established. Regular salaries were set up for soldiers. A popuation census was held. Elaborate land surveys were conducted to assess equitable taxes. New cities were founded. The areas which came under his rule were divided into provinces and governors were appointed. New roads were laid, canals were lug and wayside hotels were built. Provision was made for he support of the poor and the needy from public funds. He defined, by precept and by example, the rights and privileges of non-Muslims, an example of which is the following contract with the Christians of Jerusalem:
"This is the protection which the servant of God, 'Umar, the Ruler of the Believers has granted to the people of Eiliya [Jerusalem]. The protection is for their lives and properties, their churches and crosses, their sick and healthy and for all their coreligionists. Their churches shall not be used for habitation, nor shall they be demolished, nor shall any injury be done to them or to their compounds, or to their crosses, nor shall their properties be injured in any way. There shall be no compulsion for these people in the matter of religion, nor shall any of them suffer any injury on account of religion... Whatever is written herein is under the covenant of God and the responsibility of His Messenger, of the Caliphs and of the believers, and shall hold good as long as they pay Jizya [the tax for their defense] imposed on them."
Those non-Muslims who took part in defense together with the Muslims were exempted from paying Jizya, and when the Muslims had to retreat from a city whose non-Muslim citizens had paid this tax for their defense, the tax was returned to the non-Muslims. The old, the poor and the disabled of Muslims and non-Muslims alike were provided for from the public treasury and from the Zakat funds.
In 23 A.H., when Umar returned to Medina from Hajj;, he raised his hands and prayed,
"O God! I am advanced in years, my bones are weary, my powers are declining, and the people for whom I am responsible have spread far and wide. Summon me back to Thyself, my lord!" Some time later, when 'Umar went to the mosque to lead a prayer, a Magian named Abu Lulu Feroze, who had a grudge against 'Umar on a personal matter, attacked him with a dagger and stabbed him several times. Umar reeled and fell to the ground. When he learned that the assassin was a Magian, he sid, "Thank God he is not a Muslim."
'Umar died in the first week of Muharram, 24 A.H., and was buried by the side of the Holy Prophet (peace be on him).
The Third Caliph, Uthman (644-656 A.C.)
"Every Prophet has an assistant, and my assistant will be Uthman."(Hadith)
When 'Umar fell under the assassin's dagger, before he died the people asked him to nominate his successor. 'Umar appointed a committee consisting of six of the ten companions of the Prophet (peace be on him) about whom the Prophet had said, "They are the people of Heaven" - Ali, Uthman, Abdul Rahman, Sa'ad, Al-Zubayr and Talha - to select the next Caliph from among themselves. He also outlined the procedure to be followed if any differences of opinion should arise. Abdul Rahman withdrew his name. He was then authorized by the committee to nominate the Caliph. After two days of discussion among the candidates and after the opinions of the Muslims in Medina had been ascertained, the choice was finally limited to Uthman and Ali. Abdul Rahman came to the mosque together with other Muslims, and after a brief speech and questioning of the two men, swore allegiance to Uthman. All those present did the same, and Uthman became the third Caliph of Islam in the month of Muharram, 24 A.H.
Uthman bin Affan was born seven years after the Holy Prophet (peace be on him). He belonged to the Omayyad branch of the Quraish tribe. He learned to read and write at an early age, and as a young man became a successful merchant. Even before Islam Uthman had been noted for his truthfulness and integrity. He and Abu Bakr were close friends, and it was Abu Bakr who brought him to Islam when he was thirty-four years of age. Some years later he married the Prophet's second daughter, Ruqayya. In spite of his wealth and position, his relatives subjected him to torture because he had embraced Islam, and he was forced to emigrate to Abyssinia. Some time later he returned to Mecca but soon migrated to Medina with the other Muslims. In Medina his business again began to flourish and he regained his former prosperity. Uthman's generosity had no limits. On various occasions he spent a great portion of his wealth for the welfare of the Muslims, for charity and for equipping the Muslim armies. That is why he came to be known as 'Ghani' meaning 'Generous.'
Uthman's wife, Ruqayya was seriously ill just before the Battle of Badr and he was excused by the Prophet (peace be on him) from participating in the battle. The illness Ruqayya proved fatal, leaving Uthman deeply grieved. The Prophet was moved and offered Uthman the hand of another of his daughters, Kulthum. Because he had the high privilege of having two daughters of the Prophet as wives Uthman was known as 'The Possessor of the Two Lights. '
Uthman participated in the Battles of Uhud and the Trench. After the encounter of the Trench, the Prophet (peace be on him) determined to perform Hajj and sent Uthman as his emissary to the Quraish in Mecca, who detained him. The episode ended in a treaty with the Meccans known as the Treaty of Hudaibiya.
The portrait we have of Uthman is of an unassuming, honest, mild, generous and very kindly man, noted especially for his modesty and his piety. He often spent part of the night in prayer, fasted every second or third day, performed hajj every year, and looked after the needy of the whole community. In spite of his wealth, he lived very simply and slept on bare sand in the courtyard of the Prophet's mosque. Uthman knew the Qur'an from memory and had an intimate knowledge of the context and circumstances relating to each verse.
During Uthman's rule the characteristics of Abu Bakr's and Umar's caliphates - impartial justice for all, mild and humane policies, striving in the path of God, and the expansion of Islam - continued. Uthman's realm extended in the west to Morocco, in the east to Afghanistan, and in the north to Armenia and Azerbaijan. During his caliphate a navy was organized, administrative divisions of the state were revised, and many public projects were expanded and completed. Uthman sent prominent Companions of the Prophet (peace be on him) as his personal deputies to various provinces to scrutinize the conduct of officials and the condition of the people.
Uthman's most notable contribution to the religion of God was the compilation of a complete and authoritative text of the Qur'an. A large number of copies of this text were made and distributed all over the Muslim world.
Uthman ruled for twelve years. The first six years were marked by internal peace and tranquility, but during the second half of his caliphate a rebellion arose. The Jews and the Magians, taking advantage of dissatisfaction among the people, began conspiring against Uthman, and by publicly airing their complaints and grievances, gained so much sympathy that it became difficult to distinguish friend from foe.
It may seem surprising that a ruler of such vast territories, whose armies were matchless, was unable to deal with these rebels. If Uthman had wished, the rebellion could have been crushed at the very moment it began. But he was reluctant to be the first to shed the blood of Muslims, however rebellious they might be. He preferred to reason with them, to persuade them with kindness and generosity. He well remembered hearing the Prophet (peace be on him) say, "Once the sword is unsheathed among my followers, it will not be sheathed until the Last Day."
The rebels demanded that he abdicate and some of the Companions advised him to do so. He would gladly have followed this course of action, but again he was bound by a solemn pledge he had given to the Prophet. "Perhaps God will clothe you with a shirt, Uthman" the Prophet had told him once, "and if the people want you to take it off, do not take it off for them." Uthman said to a well-wisher on a day when his house was surrounded by the rebels, "God's Messenger made a covenant with me and I shall show endurance in adhering to it."
After a long siege, the rebels broke into Uthman's house and murdered him. When the first assassin's sword struck Uthman, he was reciting the verse,
"Verily, God sufficeth thee; He is the All-Hearing, the All-Knowing" [2:137]
Uthman breathed his last on the afternoon of Friday, 17 Dhul Hijja, 35 A.H. (June. (656 A.C.). He was eighty-four years old. The power of tHe rebels was so great that Uthman's body lay unburied until Saturday night when he was buried in his blood-stained clothes, the shroud which befits all martyrs in the cause of God.
The Fourth Caliph, Ali (656-661 A.C.)
"You [Ali] are my brother in this world and the next." (Hadith)
After Uthman's martyrdom, the office of the caliphate remained unfilled for two or three days. Many people insisted that Ali should take up the office, but he was embarrassed by the fact that the people who pressed him hardest were the rebels, and he therefore declined at first. When the notable Companions of the Prophet (peace be on him) urged him, however, he finally agreed.
Ali bin Abi Talib was the first cousin of the Prophet (peace be on him). More than that, he had grown up in the Prophet's own household, later married his youngest daughter, Fatima, and remained in closest association with him for nearly thirty years.
Ali was ten years old when the Divine Message came to Muhammad (peace be on him). One night he saw the Prophet and his wife Khadijah bowing and prostrating. He asked the Prophet about the meaning of their actions. The Prophet told him that they were praying to God Most High and that Ali too should accept Islam. Ali said that he would first like to ask his father about it. He spent a sleepless night, and in the morning he went to the Prophet and said, "When God created me He did not consult my father, so why should I consult my father in order to serve God?" and he accepted the truth of Muhammad's message.
When the Divine command came, "And warn thy nearest relatives" [26:214], Muhammad (peace be on him) invited his relatives for a meal. After it was finished, he addressed them and asked, "Who will join me in the cause of God?" There was utter silence for a while, and then Ali stood up. "I am the youngest of all present here," he said, "My eyes trouble me because they are sore and my legs are thin and weak, but I shall join you and help you in whatever way I can." The assembly broke up in derisive laughter. But during the difficult wars in Mecca, Ali stood by these words and faced all the hardships to which the Muslims were subjected. He slept in the bed of the Prophet when the Quraish planned to murder Muhammad. It was he to whom the Prophet entrusted, when he left Mecca, the valuables which had been given to him for safekeeping, to be returned to their owners.
Apart from the expedition of Tabuk, Ali fought in all the early battles of Islam with great distinction, particularly in the expedition of Khaybar. It is said that in the Battle of Uhud he received more than sixteen wounds.
The Prophet (peace be on him) loved Ali dearly and called him by many fond names. Once the Prophet found him sleeping in the dust. He brushed off Ali's clothes and said fondly, "Wake up, Abu Turab (Father of Dust)." The Prophet also gave him the title of 'Asadullah' ('Lion of God').
Ali's humility, austerity, piety, deep knowledge of the Qur'an and his sagacity gave him great distinction among the Prophet's Companions. Abu Bakr, 'Umar and Uthman consulted him frequently during their caliphates. Many times 'Umar had made him his vice-regent at Medina when he was away. Ali was also a great scholar of Arabic literature and pioneered in the field of grammar and rhetoric. His speeches, sermons and letters served for generations afterward as models of literary expression. Many of his wise and epigrammatic sayings have been preserved. Ali thus had a rich and versatile personality. In spite of these attainments he remained a modest and humble man. Once during his caliphate when he was going about the marketplace, a man stood up in respect and followed him. "Do not do it," said Ali. "Such manners are a temptation for a ruler and a disgrace for the ruled."
Ali and his household lived extremely simple and austere lives. Sometimes they even went hungry themselves because of Ali's great generosity, and none who asked for help was ever turned away from his door. His plain, austere style of living did not change even when he was ruler over a vast domain.
As mentioned previously, Ali accepted the caliphate very reluctantly. Uthman's murder and the events surrounding it were a symptom, and also became a cause, of civil strife on a large scale. Ali felt that the tragic situation was mainly due to inept governors. He therefore dismissed all the governors who had been appointed by Uthman and appointed new ones. All the governors excepting Muawiya, the governor of Syria, submitted to his orders. Muawiya declined to obey until Uthman's blood was avenged. The Prophet's widow Aisha also took the position that Ali should first bring the murderers to trial. Due to the chaotic conditions during the last days of Uthman it was very difficult to establish the identity of the murderers, and Ali refused to punish anyone whose guilt was not lawfully proved. Thus a battle between the army of Ali and the supporters of Aisha took place. Aisha later realized her error of judgment and never forgave herself for it.
The situation in Hijaz (thc part of Arabia in which Mecca and Medina are located) became so troubled that Ali moved his capital to Iraq. Muawiya now openly rebelled against Ali and a fierce battle was fought between their armies. This battle was inconclusive, and Ali had to accept the de facto government of Muawiya in Syria.
However, even though the era of Ali's caliphate was marred by civil strife, he nevertheless introduced a number of reforms, particularly in the levying and collecting of revenues.
It was the fortieth year of Hijra. A fanatical group called Kharijites, consisting of people who had broken away from Ali due to his compromise with Muawiya, claimed that neither Ali, the Caliph, nor Muawiya, the ruler of Syria, nor Amr bin al-Aas, the ruler of Egypt, were worthy of rule. In fact, they went so far as to say that the true caliphate came to an end with 'Umar and that Muslims should live without any ruler over them except God. They vowed to kill all three rulers, and assassins were dispatched in three directions.
The assassins who were deputed to kill Muawiya and Amr did not succeed and were captured and executed, but Ibn-e-Muljim, the assassin who was commissioned to kill Ali, accomplished his task. One morning when Ali was absorbed in prayer in a mosque, Ibn-e-Muljim stabbed him with a poisoned sword. On the 20th of Ramadan, 40 A.H., died the last of the Rightly Guided Caliphs of Islam. May God Most High be pleased with them and grant to them His eternal reward.
With the death of Ali, the first and most notable phase in the history of Muslim peoples came to an end. All through this period it had been the Book of God and the practices of His Messenger - that is, thc Qur'an and the Sunnah - which had guided the leaders and the led, set the standards of their moral conduct and inspired their actions. It was the time when the ruler and the ruled, the rich and the poor, the powerful and the weak, were uniformly subject to the Divine Law. It was an epoch of freedom and equality, of God-consciousness and humility, of social justice which recognized no privileges, and of an impartial law which accepted no pressure groups or vested interests.
After Ali, Muawiya assumed the caliphate and thereafter the caliphate became hereditary, passing from one king to another.
Taken from: http://www.usc.edu/dept/MSA/politics/firstfourcaliphs.html