Saint Antenor was a Time Lord, part of the small number of Renegade Time Lords who had survived in a state of history where most of the Time Lords had been killed.
With Saint Valentine, he went into exile on Earth, where he posed as Professor Atenor at a London university. He and Valentine were ultimately murdered by the assassin Nessican, acting on the orders of General Tannis.
A statue of Antenor was seen by the Seventh Doctor and Minister of Chance at the Temple of the Fourth. (WC: Death Comes to Time)