hakespeare's play Julius Caesar is based on true historical facts. In fact, many of the characters Shakespeare uses in the play were real people. Mark Antony is no exception.
He was a friend of Caesar's, and he was actually related to him. Caesar seemed to trust him, as he placed Mark Antony in command while he was away in Africa on one of his campaigns.
In Julius Caesar, Mark Antony is portrayed as a handsome athlete, a runner, and perhaps a playboy, as well. Superstitiously, Caesar tells Mark Antony to touch his wife's garment as he runs the race at the beginning of the play to free her from infertility. Mark Antony agrees to do so without question. However, the other characters don't seem to take Mark Antony very seriously and even presume that he will support the conspirators in assassinating Caesar. They underestimate him. Mark Antony's loyalty to Caesar never wavers.
