It can't very well have been, since Flanders was part of the West
Frankish kingdom while Valenciennes belonged to the German empire. The
fact that a chronicler in the late-14th century assumed a 10th-century
count named Arnulf to have been the ruler of Flanders has no real
bearing on this or on the source of his information, which was quite
probably his abbey's counterpart of the original 967 charter naming
Arnulf with the title count but (in common with the vast majority of
such documents from the time) no territorial designation at all.
> Modern historians and antiquarians found it difficult to prove that Arnulf of Valenciennes was Arnulf the son of Bertha. (Bas Aarts was still not convinced in his relatively recent articles. I think I may have convinced him now.) To make the link requires us to look at the Ghent grants which connect both people to Caribant.
The questions of how many Arnulfs there may have been in the
Valenciennes lineage and of how many other counts named Arnulf there
were in the penumbra of Flanders during the time of Bertha's son cannot
be definitively resolved on the available evidence.
On the first point, Vanderkindere made a slip over the comital title he
wrongly thought had been accorded to Isaac of Cambrai's son Arnulf in a
charter of the count of Flanders dated 5 May 941. He then supposed
(fairly reasonably, even disregarding his error) that this Arnulf son of
Isaac cannot have been the same man as Bertha's son who lived until the
second decade of the 11th century, so that there must have been two
counts named Arnulf in succession after Isaac, the second of whom was
Bertha's son. Jan Dhondt disputed this on the basis that charters were
sometimes subscribed by infants and that Isaac's son may have been a
young child in May 941 - this is true in general but implausible in the
particular instance, since the charter was not an act of Isaac regarding
property in which his infant son may have had any future hereditary
interest, and the charter was issued in Ghent where Isaac is hardly
likely to have travelled from Cambrai with an infant in tow. However, if
his son Arnulf was around 15 at the time of subscribing the 941 charter
he would have been in his mid-80s when dying in 1011/12, and this is not
so exceptional as to require an intervening generation. In other words,
for all we can prove Bertha may have been Isaac's wife, daughter or
daughter-in-law. Isaac's son (or perhaps grandson) Arnulf had lost his
own son and (at least briefly) possession of Valenciennes by the end of
what may have been a long life - and for that matter his heirless
debility in old age may have been a pretext for the count of Flanders to
take over Valenciennes in 1006.
As to how many other counts named Arnulf there may have been, this
cannot be answered with any certainty before (or after) 962, when Arnulf
the son of Adalolf was installed as count of Boulogne & Ternois in a
peace settlement with his paternal uncle Arnulf I of Flanders. Adalolf
had died in 933, and the elder of his two sons (both presumably underage
at the time) may have been called count from then on although his
namesake uncle took over Boulogne and Ternois along with the lay abbacy
of Saint-Bertin until 962. We don't know where Arnulf of Boulogne was in
this long interval, but it is more probable that he lived at the comital
court in Flanders rather than being let loose for 29 years. Adalolf's
sons had the means to oppose their uncle by the early 960s, when the
younger brother was killed and the king intervened to establish the
elder as count in Boulogne. He may have been acknowledged by his uncle
as a titular count from 933 onwards.
There were two counts named Arnulf occurring together as subscribers in
the (pseudo?-original) charter of Balduin IV of Flanders dated 1 April
988, just after the death of Arnulf II of Flanders. One of these is
sometimes thought to have been Arnulf of West Friesland, titled as count
of Ghent although his father was still living and subscribed the same
charter. This identification is further complicated by his having a
close relative - perhaps a maternal half-brother - also named Arnulf,
son of Hilduin, who was possibly count (or son of a count) of Tournai
and/or Montdidier. Fraser McNair in 2017 thought that these two Arnulfs
were both sons by different husbands of Hildegard whom he thought to
have been the sister of Arnulf I of Flanders, or perhaps his daughter.
She can't very plausibly have been his sister, because this would make
her daughter of parents who married in the 880s whereas she herself
married and had offspring in the 940s.
I think it likely that the two counts Arnulf in the 988 charter were
Bertha's son of Cambrai & Valenciennes and either Hildegard's son Arnulf
of West Friesland or Adalolf's grandson Arnulf II (Ernicule) of Boulogne
- however, if the latter was still living there is a further difficulty
in identifying a count Balduin who also subscribed the charter, who may
have been his successor. The chances of yet another count Arnulf cannot
be eliminated, but without additional evidence I can't see a solid basis
for ascribing one to Valenciennes and another to Cambrai.
Peter Stewart