This tiny brick church is all that remains of the Piast dynasty's 13th-century royal castle, though it, too, was largely rebuilt in the 15th and 20th centuries. Before WWII the church was a centre of Polish culture in a primarily German city. Poles gathered here to hear sermons and sing hymns in their own language. The last Polish mass under Nazi oppression was held here in 1939. The church was 80% destroyed in the siege of Wrocław. A plaque outside reads in part, "We are Poles...A Pole is a brother to a Pole...Poland is our mother, we cannot speak badly of our mother."