1 août 624 - Killing of Ka'b ibn al-Ashraf

Description:

He was killed on the order of the Islamic prophet Muhammad after the Battle of Badr.[2] After violating his oath to the Constitution of Medina, for common aid and defense. All the tribes of Medina has signed a document for mutual aid and protection against any outsiders. Violating such an oath in times of war would be akin to committing treason today.

https://en.wikipedia.org/wiki/List_of_expeditions_of_Muhammad

https://en.wikipedia.org/wiki/Ka%27b_ibn_al-Ashraf