 Queen Margaret I of Denmark was born at the prison of Søborg Castle, where her father, King Valdemar IV of Denmark, had confined her mother, Helvig of Schleswig.Traditionally, Archbishop Eskil of Lund is said to have expanded the previous buildings to a real castle with defensive walls and a moat.As Eskil was in close contact with Esrum Abbey, it is considered likely that he lived nearby at Søborgby.