Board Thread:Warhammer 40k General Discussion/@comment-18016240-20140707161751/@comment-4851119-20140707165047

Well, it's stated in canon that Bjorn is the oldest living loyalist SM. There may be Traitors who can match his age (the Legion of the Damned novel states that World Eaters who fought at Istvaan - and were maybe around earlier - were present on Certus-Minor) but I don't know if we have a canon source for that.