Castel aux Dix Chevaliers
A strong castle in Britain.
Its custom was that if a challenger could defeat ten knights and the castle’s lord, the castle would be liberated; if the knight could only defeat the first ten, however, he would have to take the position of lord of the castle and remain there.
The second scenario befell Erec, who relieved Hector of the responsibility. Gawain later defeated the ten knights, but not Erec, leaving himself to guard the castle for six years. Finally, Lamorat defeated all ten knights plus Gawain, ending the customs for good. Lamorat then voluntarily became lord of the castle and married its lady.
Source
Post-Vulgate Suite du Merlin | 1230-1240