Hasan ibn Ali
asan ibn Ali ibn Ab lib , commonly called Hasan, was the second Shiite Imam, succeeding his father Ali and preceding his younger brother Husayn ibn Ali. He was the elder son of Ali and Muhammads daughter, Fatimah. Muslims respect him as the grandson of Muhammad and a member of Ahl alBayt and Ahl alKisa. After the death of his father, Hasan also succeeded him as caliph. He abdicated after six or seven months, and Muawiyah, who became the first Umayyad Caliph, succeeded him. For the rest of his life, Hasan lived in Medina in seclusion until he was killed at the age of 45 or 46, and was buried in the AlBaqi cemetery in Medina. His wife, Jada bint alAshat is commonly accused of having poisoned him.
Hasan was born in the year 624 and grew up in Medina with his parents. According to Shiite belief, theirs was the only house that archangel Gabriel allowed to have a door to the courtyard of the AlMasjid alNabawi, the Mosque of the Prophet. Both Shia and Sunni Muslims consider Hasan to belong to the Ahl alBayt , the family of Muhammad, and to the Ahl alKisa , the participants of the Event of Mubahala.
Source: Wikipedia