[1] The name Frederick of Büren is known only from the Tabula Consanguinitatis, a Staufer genealogy drawn up by the monk Wibald in the mid-12th century.
[1] Büren is usually identified with Wäschenbeuren and Frederick with the count of the same name who appears as a witness in a charter of 1053.
[1] Frederick's stature in Swabia and neighbouring Alsace is proved by his advantageous marriage.
He married Hildegard of Egisheim [de], a niece of Pope Leo IX.
[1] Besides the aforementioned sons, Frederick and Louis, Frederick and Hildegard had a son named Otto [de], who became bishop of Strasbourg, and a daughter named Adelaide, who was the mother of Bishop Otto of Bamberg.