Hij is getrouwd met Mathilde Nn.
Zij zijn getrouwd
Kind(eren):
SIEGFRIED, son of --- (-1004). Thietmar names "Siegfried and his son" among those who plotted against Heinrich II “der Zänker” Duke of Bavaria in his rebellion in 984[1497]. Graf von Northeim 1002. Thietmar names "Ethelind" as wife of Count Siegfried, recording that she welcomed Ekkehard I Markgraf von Meissen at Northeim in 1002 and warned him that her husband's sons "Sigifrith and Benno" were plotting to kill him[1498].
m firstly MATHILDE, daughter of ---. The Annalista Saxo names "comitissa Machtilde" as wife of "Sigefridus comes de Northeim"[1499].
m secondly ETHELINDE, daughter of ---. Thietmar names "Ethelind" as wife of Count Siegfried, recording that she welcomed Ekkehard I Markgraf von Meissen at Northeim in 1002 and warned him that her husband's sons "Sigifrith and Benno" were plotting to kill him[1500]. The text implies that Ethelinde may not have been the mother of the sons in question. However, the fact that Siegfried's great-granddaughter was named Ethelinde suggests a blood relationship with Ethelinde senior. Another possibility is that "comitissa Machtilde" and "Ethelind" were in fact the same person, mother of both Siegfried's sons.
Graf Siegfried & his [first] wife had two children:
SIEGFRIED [II] von Northeim (-killed in battle [1025]
BENNO von Northeim (-[1047/49])
Bronnen:
[1497] Thietmar 4.1, p. 150.
[1498] Thietmar 5.5, p. 209.
https://fmg.ac/Projects/MedLands/SAXON%20NOBILITY.htm#Ottodied1083A