Building work on Flint Castle began in 1277 under Richard L'Engenour, later to become Mayor of Chester, in the reign of Edward I during his campaign to conquer Wales. The castle was strategically placed on the banks of the River Dee where materials could be carried along the river. There was also a ford across to England that could be used at low tide. The Savoyard master mason James of Saint George was overseer for the construction for a period of 17 months. Work on the castle finished in 1286.