The early medieval Château de Quierzy on the bank of the Oise, rebuilt in the fifteenth century as the fortress of the bishops of Noyon, survives as a single tower.

Quierzy was already a significant stronghold of Neustria recorded in events in the Chronicle of Fredegar at the opening of the seventh century, when Protadius, the mayor of the palace of Burgundy was the noble lover of Brunhilda, the grandmother of and regent for King Theuderic II.

The Capitulary of Quierzy was promulgated in June 877[3] by the emperor Charles the Bald, comprising a series of measures for safeguarding the administration of his realm during his second Italian expedition, as well as directions for his son Louis the Stammerer, who was entrusted with the government during his father's absence.

The capitulary thus served as a guarantee to the aristocracy that the general usage would be followed in the existing circumstances, and also as a means of reassuring the counts who had accompanied the emperor into Italy as to the fate of their benefices.

In the following century, however, Viking raids destroyed the palatium, and Hugh Capet gave his lands at Quierzy to the bishop of Noyon, who built a fortress to serve in confrontations with the powerful lords of Coucy.