One of the chief organisers of the baronial rebellion in 1215 was Robert fitz Walter (1162-1235), lord of Little Dunmow in Essex and holder of Castle Baynard within the city of London, who styled himself ‘Marshal of the Army of God’. By blood, fitz Walter was related to the Earls of Clare, Winchester and Hereford. Fitz Walter’s seal, showing him triumphing over a dragon or basilisk, displays his pride and status using the new science of heraldry. His arms (a fess between two chevrons) appear on his shield and his horse’s trappings. On a separate shield in front of the horse are the arms of the de Quincy family, once thought to represent a fellow rebel, Saer de Quincy (1170-1219), Earl of Winchester, but more probably added later in the 13th century when the matrix was re-used by one of fitz Walter’s descendants.