Hasan ibn Ali was the grandson of the Prophet Muhammad and the son of Ali ibn Abi Talib and Fatimah, the Prophet's daughter. Born in 625 CE in Medina, he is revered in both Sunni and Shia traditions. Hasan is known for his leadership qualities and his role as the second Imam in Shia Islam. He became the caliph after his father's assassination but soon faced challenges from rival factions. In 661 CE, he signed a peace treaty with Muawiya, the Umayyad leader, to avoid further conflict. Hasan's life exemplifies principles of peace and reconciliation in Islamic history.