Folcwald is the father of Finn

Finn (Frisian)

Finn, son of Folcwald, was a legendary Frisian lord. He is mentioned in Widsith, in Beowulf, and in the Finnsburg Fragment. There is also a Finn mentioned in Historia Brittonum....

, a legendary Frisian king. He is mentioned in Widsith

Tribes of Widsith

In Widsith, there is a long recital of people, clans and tribes who were known in the Germanic world of the 6th century. Here follow many excerpts from this poem with a translation and links to the tribes and people which have articles in Wikipedia, for easy...

 and in Beowulf

Beowulf

Beowulf , but modern scholars agree in naming it after the hero whose life is its subject." of an Old English heroic epic poem consisting of 3182 alliterative long lines, set in Scandinavia, commonly cited as one of the most important works of Anglo-Saxon literature.It survives in a single...

; a passage from Beowulf as translated by Seamus Heaney

Seamus Heaney

Seamus Heaney is an Irish poet, writer and lecturer. He lives in Dublin. Heaney has received the Nobel Prize in Literature , the Golden Wreath of Poetry , T. S. Eliot Prize and two Whitbread prizes...

 (lines 1089—1090) reads:

"Finn, son of Folcwald, should honor the Danes,...".

In the range of persons mentioned in the Widsith, only Finn's father is named, which seams to be particular. Maybe he was a distinctive person in those times (dark Middle Ages

Middle Ages

The Middle Ages is a periodization of European history from the 5th century to the 15th century. The Middle Ages follows the fall of the Western Roman Empire in 476 and precedes the Early Modern Era. It is the middle period of a three-period division of Western history: Classic, Medieval and Modern...

), a great king or warrior like his son. However this is unclear as written sources are missing.