Peter I of Bulgaria was the tsar of the First Bulgarian Empire from 927 until 969. The son of Simeon I, he ascended the throne following his brother's forced entry into monastic life. His reign was characterized by a significant diplomatic peace with the Byzantine Empire, established through his marriage to Maria Lekapene, and efforts to manage internal religious movements like Bogomilism. Although historical views on his effectiveness vary, he maintained a prosperous and organized state while navigating complex conflicts with the Rus and various regional rebellions.