In the interwar period, the Silesian Parliament was in the legislative authority of the autonomous Silesian voivodeship. In the years 1925—1929, a magnificent edifice was built in Katowice, which became the seat of both the Silesian Parliament and the Voivodeship Office. The building was the largest in Poland at that time. It was built in the neo- Classicist style. The Parliament Hall became a model for the Sejm of the Republic of Poland, which was being constructed at the same time.