[2] Through his mother Cunigunde, who was a granddaughter of King Louis the Stammerer of West Francia, Sigfried was a sixth-generation descendant of Charlemagne.

[4] Wigeric is also considered the founder of the House of Ardennes, and his sons, including Sigfried, would all create their own respective branches and become important rulers in Upper and Lower Lotharingia.

[9] In the mid-10th century, Siegfried acquired the rocky promontory known as Lucilinburhuc and its immediate surrounding area, as well as usage rights for the river from the Abbey of Saint-Maximin in Trier in exchange for land he owned near Feulen.

[9] The deed for the exchange was not drawn up until 987 and although the plots of land involved were tiny, the transaction was evidently a significant one, for the document bears the seals of Bruno, archbishop of Cologne and brother of emperor Otto I, Henry I, archbishop of Trier and Frederick I, Duke of Upper Lorraine, Siegfried's brother.

[10] The site chosen for the construction of the castle of Luxembourg was not only located on an easily defendable rock, but it was also not far from the intersection of the old Roman road Reims-Trier and a prehistoric path leading from Metz to Liège.

[17] At the death of Otto II in 983, Siegfried fought at the side of the dowager empress and regent Theophanu against the ambitions of King Lothair of France.