The keep is by far the most representative remnant of this military architecture. It is here at the summit of the rock that the Château des Baux first came into existence. The Lords of Baux had the rock overlooking the valley at heights of up to 20 metres carved out so as to defy anyone attempting to scale it.
The keep is largely hewn out of the rock. To construct it, the rock was extensively hollowed out. This meant that stones were on site ready to be carved, at a time when numerous châteaux were still being constructed from wood. Quarries were often far away and transporting stone was expensive.
On the lower level, the keep consisted of just one room, but from the first floor up there are three rooms measuring 35 by 12 metres. As was usual in the Middle Ages, there was no direct communication between between the lower level and the upper floors.
Today, the stone still shows traces of certain structures: arches supporting the first floor, doors and windows, holes where beams would have been fixed, the large chimney on both sides of the southern wall, the sculpted corbels that would have supported the vaulted roof: a griffin on the left and Saint George fighting the dragon on the right.