Shakespeare’s verion might be better known, but the best historical account of the death of Big Julie was written by imperial biographer (and obsequious toady) Seutonius. It is from Suetonius that we have Caesar’s famous last words (asking Brutus ‘even you, my child?’, which Shakespeare rendered as ‘et tu, Brute?’) – although curiously, Seutonius himself reports those words as claimed by others, and for himself believes that Caesar said nothing.
This is somewhat hard to believe, given that Seutonius also recounts that Caesar was attacked by 60 or more men, and received a total of 23 stab wounds from his assailants – it appears that the proximate cause of death was loss of blood. (Fun fact: Caesar’s autopsy report is the earliest one to have survived to the present day.) In a larger sense, the cause of the death of Gaius Julius Caesar was political ambition – his own, and that of others.