Gronez is a ruined castle from the 14th century, on the Gronez headland in St ouens and was held by Phillipe de Carteret, against the French when they held half of Jersey, possibly as a shelter for the farmers and people from that side of the Island, between 1461 and 1467, it was built by Sir john de Roches in 1330, at the start of the 100 years war as a place of refuge for the locals from French attacks
