Board Thread:Lore Discussion/@comment-25291590-20130317093523/@comment-9887604-20130617113913

Pelagius III in game character was classified as a Breton in Skyrim. This may lend some credence to the Septim line actually being descended from a Breton Tiber Septim, as opposed to a Nord Tiber Septim. It would stand to reason that the Breton side of the Septim line would come out more when being intermingled with the Direnni genetic code. Perhaps Breton descendents genetic code is so mixed with Atlmeri code, that when they intermingle the general rule of favoring the mother is invalid, and you will always get a Breton child.