Slangerup is a town with a population of 6,822 (1 January 2011) in Frederikssund municipality in Region Hovedstaden in the northern part of the island of Zealand (Sjælland) in eastern Denmark.

The town was established by the Viking Slangir at the time of Harald Bluetooth. King Eric I of Denmark (ca. 1070-July 1103), was born in Slangerup. In the 13th century the town was the scene of activities involving both Bishop Absalon and Valdemar the Great. Thomas Kingo grew up and was priest in the town during the 17th century.

Until January 1, 2007 Slangerup was also a municipality covering an area of 46 km², and with a total population of 9,237 (2005). Slangerup Municipality ceased as a result of the 2007 Municipal Reform (Kommunalreformen), being merged into Frederikssund municipality along with Jægerspris and Skibby municipalities. This created a municipality with an area of 260 km² and a total population of ca. 44,140.

Coordinates: 55°51′N 12°11′E / 55.85°N 12.183°E / 55.85; 12.183

Skjalm Hvide (born in the early 11th century, died 1113) is regarded as the founder of the Hvide clan, and one of the most influential and powerful chiefs in Denmark in the late Viking age and early medieval age. One of his most important strongholds was located in Jørlunde. He built the church in Jørlunde around the year 1100.

http://www.roskildehistorie.dk/stamtavler/adel/Hvide/Trylle.htm