Château de Rosamel, Château in Frencq, Pas-de-Calais, France

Château de Rosamel is a registered historical monument in Frencq featuring four residential buildings arranged around a narrow central courtyard that serves as an internal light source. The structure rises three stories above a basement level with low-pitched slate roofing, creating an inward-focused layout.

The structure rose from 15th century fortress foundations when architect Giraud Sannier directed its reconstruction starting in 1770. The rebuild continued over decades, reaching completion in 1820 and receiving historical monument protection in 1966.

The seigneurie of Rosamel was bought in 1710 by Louis du Campe, master of the waters and forests of the Boulonnais; his grandson Claude Louis Marie du Campe de Rosamel, marshal of the camps and armies of Louis XV, launched the rebuilding in 1770. His son Claude, a naval officer, became Minister of the Navy and a Peer of France. The family kept the château through the 19th century and sold it in 1919.

The building is a ruin: part of the roof and floors have collapsed, so it is viewed from outside rather than toured. The cour d'honneur is closed by a gate and flanked by two outbuildings, one still roofed, the other now open and formerly housing a chapel. The site lies 12 km from the sea and 9 km from the A16.

The 15th-century stronghold that preceded the château left no visible trace above ground; the present building stands on its foundations. The seigneurie was bought in 1710 by Louis du Campe, master of the waters and forests of the Boulonnais, and passed to his grandson Claude Louis Marie du Campe de Rosamel, who ordered the reconstruction in 1770.