The German historian Thietmar, Count of Merseburg wrote that the Daner had their main cult centre on Zealand at Lejre, where they gathered every nine years and sacrificed 99 people but also horses, dogs and hens.
Thietmar of Merseburg | Thietmar, Count of Merseburg | Thietmar |
Also, a theory has been advanced (apparently recorded by Thietmar and supported by Oswald Balzer in 1895) that Vladivoj, who ruled as Duke of Bohemia during 1002–1003, was another son of Dobrawa and Mieszko I.
By the time of the 13th century, when the pilgrim Thietmar passed the island in 1217, the entire place was inhabited by a fishing village and populated by Muslims and captive Franks.
His father was either Count William III of Weimar, his mother probably Oda, daughter of the Saxon margrave Thietmar of Lusatia.
Thietmar was a son of Siegfried the Elder, count of Walbeck (d. 15 March 991), and was related to the family of the emperor Otto the Great, and Kunigunde (ca. 956–13 July 997), daughter Henry I the Bald, Count of Stade (House of Udonids).
In January 976 Willigis probably consecrated the first Bishop of Prague, Thietmar (Dětmar) at Brumath in Alsace, whose diocese was put under his jurisdiction.