Rebels from the garrison provinces besieged ʿUthmān's house in Madinah for some forty days, demanding his abdication over grievances about appointments and revenues. He refused to shed blood in the Prophet's city, forbade the companions to fight for him, and was killed at his reading of the Qurʾān on 18 Dhū al-Ḥijjah 35 AH, aged over eighty.
The murder of a caliph by Muslims broke something that did not mend: from it flowed the demand for retribution, Ṣiffīn and the first civil war, and fault lines that still organise the map of the Muslim world. The sources dwell on the copy of the muṣḥaf stained with his blood — the same recension project that is his lasting monument.
The day is transmitted with minor variance around the ḥajj days of 35 AH.