From the English Wikipedia page on Brun I, Count of Brunswick:

http://en.wikipedia.org/wiki/Brun_I,_Count_of_Brunswick

Brun (Latin Bruno; born around 975, died around 1010), was count in the Derlingau, the Nordthüringgau, the Hastfalagau, the Salzgau, the Gau Gretinge, and the Gau Mulbeze, with Brunswick as his residence. Brun was a member of the Brunones dynasty.

Brun's father is assumed to have been Count Liudolf (died 993). In 1002, Brun married Gisela of Swabia, who later became wife of the Emperor. Their oldest son was Liudolf (about 1003 – 1038).

In 990, Brun was a member of the Saxon army that supported Mieszko I, Duke of Poland, against Boleslaus II, Duke of Bohemia, in Silesia. Brun participated in the election for King of the Romans of 1002 (after the death of Otto III, Holy Roman Emperor) as a candidate and elector. When his own candidacy failed, he supported Herman II, Duke of Swabia, whose daughter he married in the same year. Brun had been considered a legitimate candidate because he was a male-line relative of Otto III.

References

Braunschweigisches Biographisches Lexikon, Appelhans 2006, ISBN 3-937664-46-7

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• Grafen Bruno von Braunschweig aus dem Hause WERLA
• Greve av Engen, Tyskland
• Markgreve av Sachsen, Tyskland

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Identified as the father of Liudolf von Braunschweig and husband of Gisela von Schwaben in FMG Medlands:

http://fmg.ac/Projects/MedLands/HOLLAND.htm#_Toc181670242

Chapter 12. MARCH of FRISIA

The March of Frisia was presumably established by the kings of Germany as a response to the activities of Dirk III Count of Holland, whom Thietmar records (as "Dietrich the empress's nephew") attacked Adalbold Bishop of Utrecht in 1018, before his forces were attacked by the Frisians and suffered numerous casualties[815].

The precise date when the March was first established is not known. Liudolf von Braunschweig is the first person who appears with the title, from 1028.

His candidature was presumably approved because his paternal grandfather, Ekbert [I] "der Einäugige", held counties in Frisia (see the introductions to Chapters 8 and 9 above). According to Vanderkindere, Liudolf's son and grandson, both named Ekbert, were also installed in the march of Frisia[816]. Although the primary sources indicate that they held land in Frisia, their march was Meissen.

Heinrich Graf von Northeim, whose wife was heiress of the Brunswick family, was installed as Markgraf in Frisia in 1101 but was killed while trying to subdue the territory.

1. LIUDOLF von Braunschweig, son of BRUNO [I] [von Braunschweig] & his wife Gisela of Swabia ([1003/05]-23 Apr 1038).

• The Annalista Saxo names "Liudolfus comes Saxonicus, filius Brunonis de Bruneswic et Gisle inperatricis", when recording his death[817].
• His parentage is confirmed by the charter dated 1051 under which "Heinricus…Romanorum imperator augustus" donated "comitatum quem Brun eiusque filius noster frater Liutolfus nec non et eius filius Echbreht comites…in pagis Northduringen, Darlingen, Valen, Salthga, Grethe, Mulbeze" to the church of Hildesheim[818].

References:

• [815] Thietmar 8.27, p. 380.
• [816] Vanderkindere, Vol. 2, p. 288.
• [817] Annalista Saxo 1038.
• [818] D H III 279, p. 380.