 In 1254, Grosmont Castle and her sister fortifications were granted to King Henry's eldest son and later king, Edward.The Welsh threat persisted, and in 1262 the castle was readied in response to Prince Llywelyn ap Gruffudd's attack on Abergavenny in 1262; commanded by its constable Gilbert Talbot, Grosmont was ordered to be garrisoned "by every man, and at whatever cost".The threat passed without incident.