Arnulf is first mentioned (together with his parents) in 970. Like his father, his name appears in numerous Flemish documents at the time. In 983 Arnulf accompanied Emperor Otto II and future Emperor Otto III on their journey to Verona and Rome. As count he managed to expand his territories southwards. Arnulf donated several properties to the Abbey of Egmond, amongst others, Hillegersberg (which was previously called Bergan, but renamed after Arnulf's mother) and Overschie, which may have been rewards for the land-clearing activities of the monks of Egmond.
Arnulf was the first count to come into conflict with the West-Frisians and in 993 he invaded their territory, but on 18 September of that year he was defeated and killed in a battle near Winkel in West-Friesland. His son Dirk was still a boy at this time, but Arnulf's widow Luitgard managed to retain the county for her son with support from first Emperor Otto III and later her brother-in-law, Emperor Henry II.
On 20 September 993 Liutgard donated her properties at Rugge to Saint Peter's abbey of Ghent for the soul of her husband. In June 1005 she made peace with the West-Frisians through mediation by Emperor Henry.
|Offspring of Aarnout van Holland and Lutgardis von Luxemburg (955-1003)|
|Dirk III van Holland (c983-1039)||983 Gent||27 May 1039 Egmond|| Othilde von Sachsen (c989-1044)|
|Adelina van Holland (990-1045)||990||1045|| Baudouin de Boulogne (?-1033)|
Enguerrand de Ponthieu (c995-1046)
|Siegfied van Holland (?-?)|
|Count of West Frisia|
| Succeeded by|