 On 28 January 1297 St John marched with de Lacy to convey provisions to Bellegarde, which being besieged by Robert, Count of Artois.The English army was ambushed and St John's column was attacked and St John was taken prisoner along with ten other knights.St John was sent to Paris and was kept in captivity until being released after the Treaty of Montreuil in the summer of 1299.