Some 500 years after the Romans left The Irish annals record (Fir gorma) the Blue Men who were seized by the Vikings in Morocco.
The Irish Annals classify Gorm as a black Dane or black Gall (stranger). Dubh Gall means (Black foreigner)
The name Gormund is derived from Grim. The modern derivative of this is Graham or Graeme. In old Irish Grim means black.
It is said that Grahams Dyke was named after Septimus Severus, the Libyan born Roman Emperor.
In the Scandinavian sagas, Grim, son of Kveldulf, is described as black. He had a broad jaw, dark complexion, broad nose and curly hair.? The term Grim or Gorm was used to describe anyone with a dark complexion.
Whilst it cant be known whether he was of African stock, the Vikings were known to raid into Africa, so his mother could potentially be an African captive, though this pure conjecture.