Originally Posted by Winterwind
Question of my own. I recently started reading Fulgrim for another time, and while doing so noticed that, on the cover, there is a depiction of a Dreadnought. I also recall that there was at least one Dreadnought featured towards the end of Galaxy in Flames.
IIRC, the Heresy concept art books had a Custodian dreadnought, and the Contemptor dread relies on pre-heresy tech. According to Lexicanum the oldest dreadnought parts were built during the Age of Strife (M23-30) Plus, where else would the traitor legions have gotten the technology from?