The pledge and the inherited crisis
After Uthman's assassination, Madinah was politically leaderless for several days. The senior Companions — Talha, Zubayr, and others — pressed Ali to take the pledge. He hesitated, knowing the conflicts to come, and famously said: 'Leave me alone and seek someone else.' When the people insisted, he gave conditions: 'My pledge will not be in secret — it must be in the masjid, with everyone's consent.' The pledge was given. He inherited a community split between three factions: those demanding immediate retaliation against Uthman's killers, those satisfied with deferring the matter, and those who held that the killers were themselves a threat to the new caliph. Ali's position was the middle one — pursue the killers when the state had the capacity, not before.
The Battle of the Camel — Muslims fight Muslims for the first time
Aisha, Talha, and Zubayr — three of the most senior Companions — led a force from Mecca to Basra calling for the immediate punishment of Uthman's killers. Ali marched out to meet them, hoping to negotiate. They met outside Basra in 36 AH. Negotiations were nearly successful — until partisans within both armies, eager to provoke battle, attacked at dawn. The fighting was brief but devastating; Talha was killed by a stray arrow, Zubayr withdrew from the battlefield and was murdered by an outsider, and Aisha was captured. Ali treated her with the utmost honour — he sent her brother Muhammad to escort her back to Madinah with a guard of women dressed as soldiers, so that no one could say she had travelled with men. The battle is remembered as the first time Companions of the Prophet ﷺ fought each other with swords. None of them wanted it; partisans on both sides forced it.
The Battle of Siffin and the arbitration
Mu'awiyah, governor of Sham (Syria), refused to give the pledge to Ali until Uthman's killers were brought to justice. Ali insisted that pledging first was the prerequisite for any state action. The two sides met at Siffin on the Euphrates in 37 AH and fought for several months. As the battle began to turn in Ali's favour, Mu'awiyah's commander Amr ibn al-As ordered his soldiers to raise pages of the Quran on their spears, calling for arbitration by the Book of Allah. Ali knew the gesture was political, but his own army — exhausted and reluctant to keep fighting fellow Muslims — pressed him to accept. He agreed to arbitration. The arbitration itself was inconclusive and outmanoeuvred Ali politically, leaving Mu'awiyah's claim to Syria intact.
The Khawarij — the first sectarian split
A faction within Ali's own army — about 12,000 men — rejected the arbitration on principle. They held that any submission to human judgement on a question of religion was apostasy, and they declared Ali himself outside Islam for accepting it. They withdrew from his army to Harura (giving them their other name, Haruriyya) and later to Nahrawan. Their slogan was 'la hukma illa lillah' — 'no judgement except Allah's'. Ali sent Ibn Abbas to debate them; Ibn Abbas's argument convinced about half of them to return. The remaining several thousand were defeated in battle at Nahrawan in 38 AH, but the sect persisted underground and later produced the assassins who would kill Ali himself. The Khawarij are the first sectarian split in Islamic history; their hyper-literalism and willingness to declare other Muslims kuffar (the practice of takfir) is a pattern that has recurred in extremist movements across every later century.
His assassination
In Ramadan of 40 AH, three Khariji conspirators in Mecca pledged to assassinate Ali, Mu'awiyah, and Amr ibn al-As on the same night to remove all three contenders for leadership at once. Only Ibn Muljam, who targeted Ali, succeeded. As Ali walked to the masjid of Kufa for Fajr prayer, Ibn Muljam struck him with a poisoned sword across the head. Ali lived for two days. He was asked who should succeed him; he refused to nominate, leaving the decision to the community. He instructed that Ibn Muljam be treated humanely while alive — fed and given water — and executed only by the equivalent of his own attack: 'Strike one strike for one strike. And do not mutilate him; I have heard the Messenger of Allah ﷺ say: Do not mutilate, even with a rabid dog.' He died on the 21st of Ramadan, aged about 63.
His scholarship and his sayings
Ali's intellectual legacy is enormous. He is the source of more juristic rulings than any other Companion; his sermons and letters were collected into Nahj al-Balaghah, one of the great works of Arabic prose. He famously said: 'The Quran is between two covers; it does not speak — men speak through it.' His judgements on inheritance, divorce, and ritual still appear across the legal manuals of every school. He educated his sons Hasan and Husayn personally; through them and through his other children, his lineage runs through almost every major scholarly family of the Hashimite tradition. The Prophet ﷺ said of him: 'I am the city of knowledge, and Ali is its gate.' (The chain of this hadith is debated — graded hasan by some scholars, weak by others — but Ali's actual scholarship is uncontested.)
Reflection
Ali's caliphate is a tragedy in the classical sense: every choice he made was the right one, and every choice cost him something. He took the pledge to keep the community together; he was forced to fight Muslims to keep it together; he accepted arbitration to stop the bloodshed; the arbitration handed his enemies a political win; the most committed in his own army turned on him for accepting it; one of them eventually killed him. None of this was failure on his part — it was the first generation of Muslims discovering, through painful experience, that political unity after the Prophet ﷺ would require not just personal righteousness but institutions the new community had not yet built. Ali handed the next generation a hard-won lesson: the religion was preserved, the Quran was secured, the territory was vast — but the political settlement of how Muslims govern themselves remained, and remains, an ongoing test.
Primary sources
- Sahih Bukhari (the chapters on the merits of Ali)
- Sahih Muslim (chapters 32–34 on the Companions)
- At-Tabari, Ta'rikh ar-Rusul wa-l-Muluk (the chapters on Ali's caliphate, the Battle of the Camel, Siffin, the Khawarij)
- Ibn Sa'd, Tabaqat al-Kabir (the entry on Ali)
- Nahj al-Balaghah — the collection of Ali's sermons, letters, and sayings