 The region belongs almost exclusively to the Black Sea drainage basin and includes most of the large rivers flowing in Croatia.The boundaries of Croatia proper were shaped by territorial losses of medieval Croatia to the Republic of Venice and the Ottoman conquest starting in the 15th century.In effect, Croatia proper loosely corresponds to what was termed "reliquiae reliquiarum olim magni et inclyti regni Croatiae" (the relics of the relics of the formerly great and glorious Kingdom of Croatia) and the subsequent Kingdom of Croatia within the Habsburg Monarchy.