 The title "tsar", the Bulgarian form of the Latin "Caesar", was first adopted and used in Bulgaria by Simeon I, following a decisive victory over the Byzantine Empire in 913.It was also used by all of Simeon I's successors until the fall of Bulgaria under Ottoman rule in 1396.After Bulgaria's liberation from the Ottomans in 1878, its first monarch Alexander I adopted the title "knyaz", or prince.