March 28, 193 A.D. - The Roman Emperor Pertinax is assassinated by his Praetorian Guards. They sold the throne at auction to Didius Julianus, who reigned for a mere 2 months and incited a 4-year Roman Civil War.
March 28, 364 A.D. - Roman Emperor Valentinia I names his brother, Flavius Valens, co-Emperor. He ruled the eastern part of the Roman Empire during his 14-year reign.
March 31, 307 - Roman Emperor Constantine marries Fausta, daughter of the former Roman Emperor Maximian.
March 31, 250 A.D. - Roman Emperor Constantius Chlorus is born.