Katarina Vukcic-Kosaca (1424-1478), the last Queen of Bosnia, ardent Catholic, wife of the Bosnian King Stjepan Tomasevic (1461-1463), is still one of the most beloved personalities among the Croats living in Bosnia. When Bosnia fell under the Ottoman rule in 1463, her two children (a boy and a girl) had been taken to slavery and educated in the spirit of Islam, her husband decapitated. She managed to escape to Dubrovnik, and then to Rome, where she had been deeply involved in the humanitarian activity of the Franciscan community (Aracoeli) becoming Franciscan Tertiary herself, to help Bosnian Croats under the Turkish rule.

The above portrait of Katarina Kosaca, Bosnian Queen, was made by Giovanni Bellini, held in the Capitol Gallery of paintings in Rome.

She built a church of St. Katarina in a picturesque Bosnian city of Jajce (totally destroyed by the Serbs in 1993). Despite her very difficult position, she had always been treated as a Queen of Bosnia in official circles. Tormented by the tragedy of her homeland, lawful Queen Katarina bequested her Bosnian Kingdom to pope Sixto IV and Holly See in 1478 (“…in case that my islamised children are not freed and returned to Catholic faith“). Her grave in the Aracoeli church in Rome had a Croatian Cyrillic inscription until 1590 (with the coat of arms of the old Bosnian Kingdom and of the Kosaca family), when it had been replaced by translation into Latin. Even today, after more than five centuries, Croatian women wear black costumes in some parts of Bosnia in remembrance to her tragic life and kindness towards poor people. Beatified.

The seat of Bosnian kings in 14th and 15th centuries was Bobovac, about 50 km north of Sarajevo. Its walls were about 1100 meters long. Many documents are preserved mentioning Bobovac. It fell under the Turks in 1463, which meant the fall of mediaeval Bosnian state.

After the catastrophic defeat of the Serbs in the Kosovo field in 1389, on whose side both Croatian forces from Bosnia and Albanian troops had also participated, Serbia became a vassal state to the Turkish Ottoman Empire.