Florian (Latin: Florianus; AD 250 – c. 304) was a Christian holy man and the patron saint of chimney sweeps, soapmakers, and firefighters. His feast day is 4 May. Florian is also the patron saint of Poland; the city of Linz, Austria; and Upper Austria, jointly with Leopold III, Margrave of Austria.
Florian was adopted as patron saint of Poland in 1184, when Pope Lucius III consented to the request of Prince Casimir II to send relics of Florian to that country. Kraków thus claims some of his relics.
Thus Florian also became important to Lithuania, ever since the Krewo Agreement of 1385 (Polish–Lithuanian union) and the subsequent marriage of Queen Jadwiga of Poland to Grand Duke Jogaila of Lithuania. Jogaila was a lifelong pagan and vowed to adopt Catholicism upon marriage by signing the Union of Krewo on 14 August 1385. The Act imposed Christianity in Lithuania and transformed Poland into a diarchy, a kingdom ruled over by two sovereigns; their descendants and successive monarchs held the titles of king and grand duke respectively.