Day of Republika Srpska (Serbo-Croatian: Dan Republike Srpske / Дан Републике Српске) is a national holiday of Republika Srpska proclaimed unconstitutional by the Constitutional Court of Bosnia and Herzegovina. The holiday is celebrated on 9 January, and its unofficial patron saint is Saint Archdeacon Stephen—historically being patron saint of medieval Kotromanić dynasty kings bearing their first name after him—which falls on the same day.