Northern British 5-7th Century Army composition?

[Anton]

The paternal line is what counted in Celtic law to qualify you for inheritance great or small.

If we look at Koch treatment of Y Gododdyn we can see a very well placed young man with an obviously German father likely leading the Teulu of the Gododdyn.  In terms of elite social integration he is an exemplar.  His mother in my view was from the royal dynasty. I'd say probably a sister of the Rí.  A sister's son was favoured as a trusted relative precisely because he could not inherit and the familial relationship between uncle and nephew was often genuinely a close one. It is easily possible to imagine that the young man was foster son to the Rí and foster brother to royal offspring. 

Aneirin tells us that this young man was listened to by prominent noble warriors and then adds- although his father was no lord. The point being that father may well have been a lord of Angles but that brought no status in the internal politics of the Votadini.

Likewise the Laws of Ine benefit Saxons above Welsh and presumably the right to claim those benefits was strictly policed by those who were undeniably Saxons.  Perhaps maternal descent was enough to qualify but I'm insufficiently informed to know that.

Intermingled families would need to pick their best options bot choice may have been constrained.

[Imperial Dave]

I reread Koch's essay on Y gododdin today and agree re the Germanic element of leadership of The Votadini ie Yrfai son of Wolstan (Wulfstan). Makes interesting reading then that the traditional view of 'British' forces engaging with 'Germanic' forces at Catraeth!. The truth appears to be somewhat muddier than that for sure but in the context of the socio-political landscape of the time, completely understandable