Bifficus Antanneny was a distant ancestor of the Tannen family that lived in ancient Rome. When Marty McFly and Emmett Brown traveled to ancient Rome in 36, Antanneny challenged "Marticus" to a chariot race. Although Marty is annoyed at Bifficus' attitude, his friends Vern and Jules warn that they could indirectly ruin Hill Valley as they could return to find no United States, instead that it would be under a still-existent Roman Empire. Ergo, there would be no way of knowing if Hill Valley would have been discovered by the Romans, or if so, whether the Hill Valley citizens would be oppressed as many people were by the Ceasars. Marty agrees to let Bifficus win, as he is a favorite of Caligula. It was later revealed that Caligula earned the reputations of one of the worst emperors, and his disastrous policies helped to run Rome into the ground (as occurred 440 years later), thus ensuring Hill Valley's survival.