The keep, which was only exposed in the 1990s, is situated in the north-west part of the Castle Hill. It was originally a circular structure with a height of at least 25 metres, a diameter of 12 metres and 4.2 metre thick walls. The interior has a diameter of only 3 metres. The tower represented the most secure defensive element and also functioned as a refugium – that is a refuge in the case of the castle’s ramparts being breached. Provided there was sufficient water, food supplies and weapons the tower could give protection for some time until the arrival of reinforcements. The keep was built in the 13th century either during the times of the castellany or immediately after the founding of the autonomous Duchy of Cieszyn.