The fortifications of Kingston upon Hull consisted of three major constructions: the brick built Hull town walls, first established in the early 14th century (Edward I), with four main gates, several posterngates, and up to thirty towers at its maximum extent; Hull Castle, on the west bank of the River Hull, protecting Hull's river harbour, constructed in the mid 16th century (Henry VIII) and consisting of two blockhouses and a castle connected by a curtain wall; and the later 17th century Citadel, an irregular triangular, bastioned, primitive star fort replacing the castle on the east river bank.