21 Ramadan is the twenty-first day of the ninth month (Ramadan) of the Islamic calendar.

In the conventional Lunar Hijri calendar, this day is the 257th day of the year.

Deaths

• 40 AH – Ali ibn Abi Talib, the first Imam of Shiites and the fourth Caliph of Sunnis^[1][2][3][4]
• 726 AH - Osman I, the founder of the Ottoman dynasty^[5][6]
• 1104 AH - Al-Hurr al-Amili, a Shia scholar and Faqih, author of Wasa'il al-Shia^[7][8]
• 1028 AH - Seyyed Majed Hosseini Bahrani,^[9] a Shia scholar, Faqih and poet^[10][11]
• Moses - Prophet of the Israelites (according to the narrations)^[12][13]
• Joshua - Moses' assistant and his successor (according to the narrations)^[13][14]

Events

• 40 AH - The beginning of the caliphate of Hasan ibn Ali, the older son of Ali and Fatimah, and a grandson of the Islamic prophet Muhammad, the second Shi'i Imam^[15][16][17]
• 40 AH - The allegiance of the people of Kufa to Hasan ibn Ali for the caliphate^{[18][19][20][21]}
• 40 AH - Retribution of Abd al-Rahman ibn Muljam, the killer of Ali (1st Imam of Shia)^{[22][23][24][25]}
• The day of the revelation of the Quran, holy book of Islam (according to persian narrations)^{[26][27][28][29][30]}

Holidays and observances

• The second Qadr Night of Ramadan according to Shiites, holding an official nightlife worship ceremony called Ehya night in Iran^[31][32][33]
• Day of martyrdom of Imam Ali, an official holiday in Iran^[34][35]