The name Medemblik probably comes from the river Leeck or Middel-Leeck; as early as the 10th century, a stream is called the Medemalaca. Medemblik is the smallest, but also the oldest city in West Friesland on the former Zuiderzee. Excavations have shown that Medemblik already existed as an inhabited place for a long time, when Floris V set up his forced castle against the West Frisians to be subjugated. Medemblik received city rights in 1289 from Count Floris V, who according to tradition built Radboud Castle on the remains of a castle founded in the seventh or eighth century. The castle has endured many an enemy attack. In 1426 the castle was a battle scene for the Hoekse and Kabeljauwse Twisten. The first port in Medemblik was dug parallel behind the east-west running seawall. The Oosterhaven was dug in 1599 and the Westerhaven around 1632. Wharfs, ramps and a naval yard were built on the West Island, which later became a training institute for the navy. In 1850 the training institute was moved to Den Helder and the building, which is still called Landswerf, became a state mental institution. Now it is in use as a youth housing building. In 1872, the Pekelharinghaven had largely silted up and the municipality decided to fill in the remaining part. The port was initially used as agricultural land, in 1930 it was decided to convert the port into a sports field and in 1989 the port became water again for water sports.