Old palace of Świerklaniec, Former palace site in Świerklaniec, Poland

The Old palace of Świerklaniec no longer exists: it was a castle on an oval plan about 42 by 48 m, surrounded by a moat on a marshy island in the Brynica valley. Its brick perimeter wall stood on stone foundations, with a Gothic dwelling house and a rectangular gate tower. Around 1670 the inner wall was built up to form a courtyard about 15 by 28 m, and around 1849 neo-Gothic wings and two crenellated towers were added.

The castle probably originated in the 14th century as an oval stronghold on an island in the marshy Brynica valley. Around 1670 the Donnersmarcks rebuilt it in Baroque form, filling the inner side of the walls to create a courtyard about 15 by 28 metres. Around 1849 they added neo-Gothic wings and two crenellated towers. Plundered and burned in 1945, the ruins were blown up in September 1962 despite a 1961 order to rebuild.

The German name Schloss Neudeck came from the old German name of Świerklaniec, Neudeck; Polish sources also call it the Old Castle or Piast castle, to distinguish it from the 19th-century new palace. After the Donnersmarck division of 1671 it was the seat of the Świerklaniec-Tarnowskie Góry line. The interior hall shown in photographs had a painted coffered ceiling and a tiled stove.

The castle no longer exists: it was blown up in September 1962, so only its site in the Świerklaniec park, on the marshy Brynica valley floor, can be visited. Look for the oval outline of the former island and moat, roughly 42 by 48 m, with the entrance on the western side. The later palace complex nearby includes the Mały Wersal palace, the Pałac Kawalera and a landscape park.

The castle was blown up with explosives in September 1962, despite a December 1961 ministry order to rebuild it; the regional council in Tarnowskie Góry had commissioned demolition instead. The provincial conservator only learned of the destruction on 30 November 1962, and the ruin was then struck from the register of monuments.