Assassination of Uthman
656 murder of the third Rashidun caliph in Medina
Uthman ibn Affan, the third Rashidun caliph, who ruled from 644 to 656, was assassinated at the end of a siege upon his house in 656. This was initially a protest but escalated into a siege following the death of a protester. The protesters-turned-rebels had demanded a new caliph, which Uthman refused.
From Wikipedia, under CC BY-SA. More on occurri.