The Tenczyn Castle, otherwise known as the Tęczyn Castle, is a medieval castle in the village of Rudno, Poland. It was built as a seat of the powerful Tęczyński family. The castle fell into ruin during the Deluge in mid-17th century, after being pillaged and burned by Swedish-Brandenburgian forces looking for the Polish Crown Jewels and rumored treasures of the Tęczyński family. Subsequently rebuilt, after a fire in the mid-18th century it again fell into disrepair and remains in that state to this day.