Board Thread:Warhammer 40k General Discussion/@comment-25618639-20150112024430/@comment-26859246-20150905120126

Yes indeed It's possible that there were thousand son astares on that fleet that managed to survive prospero and likely stayed loyal. This could be where the BR are descended from

71.232.5.129 wrote: There is the interesting little point that Magnus did order his fleet to retreat from the Burning of Prospero without them knowing the details of his little fall from grace.