Edward Grim was a clerk from Cambridge who was visiting Canterbury Cathedral on Tuesday 29 December 1170 when Thomas Becket was murdered. He subsequently researched and published a book, Vita S. Thomae (Life of Thomas Becket), published in about 1180, which is today known chiefly for a short section in which he gives an eyewitness account of the events in the Cathedral. He himself attempted to protect Becket, and sustained a serious arm wound in the attack. Whilst there are four other accounts of the events of that day, Grim was the only eyewitness to actually observe the killing itself. Little else is known of his life, before or after the murder.