The Field Cathedral of the Polish Army (Polish: Katedra Polowa Wojska Polskiego, also known as the Church of Our Lady Queen of the Polish Crown) is the main garrison church of Warsaw and the representative cathedral of the entire Polish Army. In the past the church served a variety of communities and roles: it used to be the church of the Collegium Nobilium and in the 19th century was also turned into a Russian Orthodox church.