Nobody knows exactly what Julius Caesar's last words were. In "The Lives of Twelve Caesars," written 165 years after the assassination, the historian Gaius Suetonius Tranquillus writes:

When [Caesar] saw that he was beset on every side by drawn daggers, he muffled his head in his robe, and at the same time drew down its lap to his feet with his left hand, in order to fall more decently, with the lower part of his body also covered.

But Seutonius also notes that "some have written" that when Caesar saw his close friend Marcus Brutus rushing at him, he said in Greek, "Kai su, teknon," a phrase that is notoriously difficult to translate but is often rendered "You too, my child?"

Some historians have taken this phrase not as one of shock at Brutus' betrayal, but as a threat to the conspirator, as in "Your turn next, kid."

By the time Shakespeare famously deployed "Et tu, Brute?" (in the 1599 play bearing the Roman emperor's name), the phrase was already well known to English audiences, having appeared in a 1582 Latin play on the same subject performed at Oxford.