An essay about the history of the archiepiscopal see of the small city of Split on the Adriatic coast of Dalmatia was written in the 13th century. Archdeacon of the local church Thomas. It is of particular interest to researchers and lovers of medieval history, primarily due to the abundance of often unique historical material collected in it. Its content turns out to be much broader than the topic stated by the author himself, and in addition to local history subjects, it covers the history of Dalmatia, Croatia and Hungary from early antiquity to the middle of the 13th century. Thomas was a contemporary, witness and chronicler of many significant events in European history related to the Crusades, the activities of the mendicant orders, the struggle of the popes with the German emperors, and the invasion of Tatar-Mongol troops into Western Europe.