The Château d'Étampes was an early 10th-century stronghold of Robert the Pious, King of France, that comprised both a palace proper and motte.

Between 1130 and 1150, a new castle was created overlooking the valley, culminating in a strong keep or donjon: the present Tour de Guinette.

The architectural aspects of this former royal castle are known from contemporary images, including the Très Riches Heures du duc de Berry.

The Tour de Guinette was in the centre of the castle and was surrounded by a rectangular curtain wall, punctuated by corner towers.

This interesting plan is the result of tactical experimentation that the keep underwent during the mid-12th century to improve the defence of towers against missiles and to reduce dead ground.