On this day, 545 years ago died Katarina Kosaca, the Queen consort of Bosnia as the wife of the penultimate Bosnian king Stjepan Tomas (Stephen Thomas). Also known as Catherine of Bosnia, the queen died in Rome and, according to her wish, was buried before the main altar of at the Basilica of Santa Maria in Ara Coeli.

She was the daughter of Herzeg (duke) Stjepan Vukcic Kosaca, a powerful feudal lord, after whom the southern Herzegovina region was named.

Katarina was born in Blagaj near Mostar. After she married the Bosnian king Stjepan Tomas in 1446, Herzegovina and Bosnia were united.

Since Stjepan Tomas promised the pope that he would eradicate the Bogomils (a Christian sect) from his kingdom, twenty-two-year-old Katarina became a Roman Catholic. As the Bosnian queen, she became a strong supporter of Catholicism and the Franciscans.

Stjepan Tomas Kotromanic, the Bosnian king, had two children with Queen Katarina: Sigismund (Žigmund), Katarina and a third child about whom almost nothing is known. They dined in the royal town of Bobovac near Kraljeva Sutjeska, central Bosnia.

King Stjepan Tomas died under unclear circumstances on July 10, 1461. He was succeeded by his son from a previous marriage, Stjepan Tomasevic.

Queen Catherine was then given the title Queen Mother and continued to live at the royal court. After her husband's death and the Ottoman conquest of Bosnia, she left for Rome via Dubrovnik. There she advocated for the continuation of the tradition of the Bosnian Kingdom, of which she was the queen-widow.

She died in Rome, approximately 15 years after the Ottoman conquest of Bosnia.

Katarina Kosaca was buried in the famous Basilica of Santa Maria in Ara Coeli, located in the very center of Rome, right next to the Capitoline Square (Piazza del Campidoglio) and only a hundred meters from the Roman Forum.

After her death, she was proclaimed a Blessed of the Catholic Church.

Katarina Kosaca is often referred to “the last Queen of Bosnia”.