and the nearest islands were settled by tribal Jutes. The Jutes migrated to Great Britain eventually, some as mercenaries of Brythonic King Vortigern, and were granted the south-eastern territories of Kent, the Isle of Wight and other areas, where they settled. They were later absorbed or ethnically cleansed by the invading Angles and Saxons, who formed the Anglo-Saxons. The remaining Jutish population in Jutland assimilated in with the settling Danes. Valdemar's Zealandic Law governed was a civil code enacted in the 13th century. Prior to the adoption of the Jutlandic, Zealandic and the Scanian laws, there had been no uniformity of laws throughout settlements in Denmark. Ringsted and later Roskilde were the first important political and religious centres on the island, a role later taken over by Copenhagen. Other important religious centres prior to the Reformation were Sorø Abbey at Sprø and Esrom Abbey at Rsrum. With its strategic location at the entrance to the Øresund, especially after the construction of Kronborg Castle and the introduction of Sound Dues, Helsingør would later develop into the most important town and seaport outside Copenhagen. Most of North Zealand was for centuries, starting in the late 16th century, owned by the crown and used mainly as a royal hunting domain. Local manors played a central role in the economy on the rest of the island. Early industrial centres outside Copenhagen included Mølleåen with its watermills, the Kronborg Arms Factory at Hellebæk, Johan Frederik Classen's Frederick's Works at Frederiksværk and Niels Ryberg's Køng Textile Factory at Vordingborg. Substantial parts of the southernmost part of the island was in the 18th century part of Vordingborg Cavalry District. The first railways on the island were constructed by Det Sjællandske Jernbaneselskab (1847-1888). The first section opened between Copenhagen and Roskilde in 1847. Mythological origins In Norse mythology as told in the Gylfaginning, the island was created by the goddess Gefjun after she tricked Gylfi, the king of Sweden. She removed a piece of land and transported it to Denmark, which became Zealand. The vacant area was filled with water and became Mälaren. However, since modern maps show a similarity between Zealand and the Swedish lake Vänern, it is sometimes identified as the hole left by Gefjun. Gefjun is queen of King Skjöldr, eponymous ancestor of the Scyldings, related to the etymological debate. Geography Zealand is the most populous Danish island. It is irregularly shaped, and is north