Board Thread:Community Decisions/@comment-24909831-20170817161658/@comment-24909831-20170818084316

I suggest: 0.000.115.M42, at the end of the Indomitus Crusade.

It is quite clear that the Crusade did not begin in 0.999.999.M41, but calculating from the Gathering Storm 3 book, sometime around 001.M42 at the very earliest. Warp jump from Ultramar to Maelstrom would take ~40 years, but maybe (likely) Guilliman has his private lane on Warp to speed things up.