Al-Ḥasan ibn Alī ibn Abī Ṭālib (Arabic: الحسن ابن علي ابن أبي طالب‎‎‎, 624–670 CE), commonly known as Hasan or Hassan, is the eldest son of Muhammad's daughter Fatimah and of Ali, and the older brother to Husayn. Muslims respect him as a grandson of the Islamic Nabi (Arabic: نَـبِي‎‎, Prophet) Muhammad. Among Shia Muslims, Hasan is revered as the 2nd Imam by Twelvers and Zaydis, and as the 1st Imam by Musta'li Isma'ilis. Sunni Muslims revere him as the 5th caliph (Arabic: خـلـيـفـة‎‎, 'Successor'), having briefly succeeded his father after the latter's assassination at the hands of the Kharijite. He abdicated after six or seven months to Muawiyah I, who succeeded him as the 6th caliph, the second of the Umayyad caliphs after Uthman, and founder of the Umayyad dynasty. Al-Hasan was known for donating to the poor, his kindness to the poor and bondmen, and for his knowledge, tolerance and bravery. For the rest of his life, Hasan lived in Medina, until he died at the age of 45 and was buried in the Jannat al-Baqi cemetery in Medina. His wife, Ja'da bint al-Ash'at, is commonly accused of having poisoned him.

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