I have been looking at my old saved pages of Solmyr's vassalage rules and the State Church rules in the book of Priestcraft.

I think that Solmyr has a good idea according to the copy of the rules I have, which may be updated by now, however I think that vassalage should be similar to the State Church rule.

If someone submits to another power, swear fealty to another lord or give a church recognition for being a state faith that the submitter should lose a bloodline strength. Even if it is willing or forced for one's own line is weakened by such a submission regardless if it is full of honor or good for the common wellfare of the state. The dominant should then receive the +1 str and perhaps this should include the church, or perhaps just landed lieges? The papacy?

Now if that is not agreeable I do then think the vassalage should at least benefit the liege more than the vassal in a +2 to the liege and +1 to the vassal. I still think the vassal should lose.

This could explain how the house of Avan has a 70 bloodline strength. Taeghas, Brosengae, PAI, Mieres, and WIT is +5. That is just a side note.