The furthest tower to the East is the Develin Tower, dating back to the reign of King Edward 1st
. Although partly rebuilt during the seventeenth century it was actually refaced in the nineteenth century. In the late 1500's a causeway ran from the Develin Tower across the moat to the since demolished Iron Gate. The position of this tower provided it with an excellent defensive view northwards towards Brass Mount. Unfortunately it is not open to the public.