Caliphate
The Shia view is that Ali’s right to the caliphate was usurped and his family abused by Abu Bakr but Ali, Hasan and his younger brother Husayn ibn Ali valued the Muslim community's stability above their own rights, even going to defend the third caliph Uthman before Ali himself received the caliphate.
Upon the death of Ali in Kufa a new caliph had to be elected. According to Ali's appointment before his death the choice was restricted to Hasan and his younger brother Husayn. The latter did not claim the caliphate so Kufi Muslims gave their allegiance (bay'ah) to Hasan without dispute. Most caliph chronologies do not include Hasan ibn Ali among the Rashidun Caliphs. However, many Sunni Muslim historians, such as Suyuti, Ibn al-Arabi, and Ibn Kathir accept Hasan ibn Ali as the last such caliph.^
- Suyuti in The Khalifas who took the right way page 9 and History of the Caliphs Vol 12
- Ibn al-Arabi in his Sharh Sunan al-Tirmidhi 9:68-69 ref
- Ibn Kathir in The Beginning and the End Vol 6 page 249-250
Muawiyah ibn Abi Sufyan, who had a long-running dispute with Ali, summoned the commanders of his forces in Syria, Palestine, and Transjordan to join him in preparation for battle. He first attempted to negotiate with Hasan, sending him letters asking him to give up his caliphate, believing he could thus avoid killing fellow Muslims and avoid lingering questions regarding his legitimacy should he kill Hasan outright. Most historians say that large sums of money and promises of vast properties and governorships of provinces were offered to commanders of Hassan's army who left him,one of which was ubaydallah ibn al abbas,the commander of Imam Hassan army and that Muawiyah was not interested in the functions of preaching piety or theology but in expanding his sphere of influence in the territories already conquered by the Muslims and in further conquests to the north and north west of Syria.
Negotiations failed and Muawiyah decided to march against Hasan's army of forty thousand with his own army, claimed to have numbered sixty thousand fighters. The two armies faced each other near Sabat. Hasan is said to have given a sermon in which he proclaimed his hatred of schism and appealed to his men to follow his orders even if they did not agree with them. Some of the troops, taking this as a sign that Hasan was preparing to give up battle, rebelled and attacked him. Hasan was wounded but loyal soldiers surrounded him and managed to kill the mutineers. One commander, Ubayd-Allah ibn Abbas, deserted him and joined Muawiyah’s forces.
The two armies fought a few inconclusive skirmishes. Hasan was distressed, understanding that the engagement of Muslims in a battle against each other would mean a loss of many: Muawiyah also had his concerns about being forced into a battle and sent two men from the Banu Quraish to negotiate a settlement. Shia scholars quote hadith from later Shia Imams to the effect that Hassan lacked the support to fight and win and so ceded power to Muawiya, signing an agreement that he would return the caliphate at his death. According to Shia scholars Hasan stipulated that the caliphate should be returned to him if he was still alive after Muawiyah's death, otherwise it should be given to his younger brother. According to Sunni scholars Hasan stipulated that Muawiyah should follow the Qur'an and the Sunnah, allow a parliament (shura) as regards the caliphate after his death and refrain from any acts of revenge. Muawiyah accepted the conditions attached to the peace treaty;
- the enforced public cursing of Ali, e.g. during prayers, should be abandoned
- Muawiyah should not use tax money for his own private needs
- there should be peace: followers of Hasan should be given security and their rights
Muawiyah proceeded to Kufa and demanded that the Muslims there pledge allegiance to him as caliph. He also asked Hasan to join him and support him in the fight against the rebellious Kharijites. Hasan is claimed to have written to him in response: "I have abandoned the fight against you, even though it was my legal right, for the sake of peace and reconciliation of the Muslim congregation (ummah). Do you think that I shall then fight together with you?"
Muawiyah did not comply with the terms of the treaty, saying to the people of Kufa, “do you think I have taken power to teach you? No, I have taken power and if any one of you tries to disagree with me he shall pay the costly price of the loss of his head.” He carried out his ambition of keeping the power in his family by nominating his son Yazid as caliph after him. But the decision stirred widespread agitation, particularly amidst prominent personalities such as Hussain, Abdul-Rahman ibn Abu Bakr, Abdullah ibn Umar, Abdullah ibn Al-Zubayr and others.
Read more about this topic: Hasan Ibn Ali