In 1457, King Henry VI gave the Marcher Lordship (and associated Earldom) to Jasper Tudor, his half-brother, who agreed to refurbish and improve Tenby's defences by dividing the cost between himself and the town's merchants. Improvements included widening the dry ditch along the outside of the town walls to 30 feet (9.1 m). Raising the wall's height to include a second tier of higher arrow slits behind a new parapet walk and adding additional turret towers to the ends of the walls where they abutted the cliff edges.