Bulgarian Empire
In modern historiography, the state is called the "Second Bulgarian Empire", "Second Bulgarian Tsardom", or the "Second Bulgarian Kingdom" to distinguish it from the First Bulgarian Empire. An alternative name used in connection with the pre-mid 13th century period is the "Empire of Vlachs and Bulgarians"; variant names include the "Vlach–Bulgarian Empire", the "Bulgarian–Wallachian Empire", or the "Romanian–Bulgarian Empire"; the latter name was used exclusively in Romanian historiography.