Circa mid 14th century the Balkans were politically disunited into a number of small states frequently in competition with each other and there was no single strong entity with a powerful enough army to withstand the Muslim invaders. In addition to the mainly Orthodox countries such as Bulgaria, Byzantium and Serbia, there were a number of Catholic possessions to the west and south held by Venice, Genoa and the Kingdom of Hungary as well as Kingdom of Bosnia whose Bosnian Church (closely related to the Bogomils) was considered heretic by both Orthodox and Catholics. Religious dissimilarity was thus also a source for constant political tensions in the region.