 The earliest mention of the town's coat of arms is from 1421, although it is believed to have been arranged since the beginning of the 14th century.A document in the town archive of Thorn (Toruń) dating from before 1400 used a sigil with the name "GRVNINBERG", an early form of the German name "Grünberg".In 1294, Duke Henryk III of Głogów, founded a church in honour of Saint Hedwig, patron saint of Silesia.