Ulf married Estrid SVEINSDÓTTIR, daughter of King Sveyn I "Forked-Beard" HARALDSSON of Denmark and Swietoslava (Sygryda) "The Haughty" PIAST Queen of Sweden, Norway & Denmark. (Estrid SVEINSDÓTTIR died on 3 Feb 1014 in Gainsborough, Lincolnshire, England.)