Louis of Orléans, king Charles V's son, raised a fortress in 1393 on the foundation of the old 12th century castle belonging to Nivelon de Pierrefonds. So it became the fief of the D'Orléans family: Pierrefonds became an important place, moult fort défensable et bien garni et rempli de toutes choses appartenant à la guerre ("a pretty well defensive castle with lots of things inside to make war!")! Besieged by the Burgundians then by the English, gave back to the Crown and restored by Louis XII, Pierrefonds was besieged by the League in 1589, led by Antoine de Saint-Chamand.
This one gave it to a man called Rieux. A tough guy, this captain! The Royal army besieged it 3 times, but in vain: Rieux in his castle resisted! The young king Louis XIII ordered to cardinal Richelieu to demolish the fortress, saying that combien il était utile pour le bon repos et tranquillité de ses sujets de la province de l'Ile-de-France que le château de Pierrefonds soit démoli, "castle of Pierrefonds must be destroy, for the tranquillity of Ile-de-France's inhabitants"...
So, the fortress was abandoned... Until the Revolution, it belonged to the d'Orléans family, but after that Pierrefonds was sold and owned by Napoléon in 1810. But it was Napoléon III who improved the image of the castle: in 1858, architect Viollet-le-Duc restored the building. The huge building site cost 5 millions of francs (three-quarter of the sum were taken on Napoléon III's fortune), but they transformed Pierrefonds into a perfect Troubadour masterpiece!
Troubadour style? Funny name! It was born in the 19th century and included paintings, furniture or objects which were inspired by an idealized Middle-Ages... often kitsch! Troubadour style was Viollet-le-Duc's trademark.