In Iran, the public holiday of the Death of Prophet Muhammad and the Martyrdom of Imam Hasan is observed annually on Safar 28. This day commemorates the death of Prophet Muhammad, who is regarded as the last prophet in Islam, and the martyrdom of his grandson, Imam Hasan, the second Shiite Imam. While the Prophet Muhammad passed away in Medina in 632, Imam Hasan, who was caliph for a brief period in 661, was poisoned in a plot arranged by Muawiya, leading to his death on Safar 28, 669. The observance is primarily recognized by Shiites, as Sunnites do not mark this day as significant. During this holiday, people in Iran engage in various religious activities to honor these pivotal figures in Islam.