In the following years, Queen Margaret acquired large parts of Schleswig as security (Tønder fief, Frisland, episcopal manors in Svabsted and Stubbe) and by purchase (Trøjborg, Skinkelborg and Grødersby); King Erik took over Haderslev fief as security from the fiefholder Helene Ahlefeldt, and the queen, Flensborg.
The present comital family number the noble families Ahlefeldt, Frijs-Frijsenborg, Kaas, Trolle, Thott, Ulfstand, Ulfeldt, Huitfeldt, Sehested, Gyldenstierne, Rosenkrantz, Rantzau, Reventlow, Brahe, Ruud, Grubbe, Gabel, Krag to Juellund, and Krag-Juel-Vind-Frijs among their ancestress-linked relatives.
His godparents are his maternal uncle, John Stuart Donaldson, the Prince of Asturias, the Hereditary Prince of Sayn-Wittgenstein-Berleburg, Count Michael Ahlefeldt-Laurvig-Bille, Baroness Helle Reedtz-Thott and Caroline Heering.
In August 1946 Alvensleben married Astrid von Brand (widowed von Brockdorff-Ahlefeldt) and in 1952 he became an administrator of the von Brockdorff estate Ascheberg near Plön.