Siege of Velorum Prime

The Siege of Velorum Prime was an Imperial excoriation campaign conducted by both the Tempest Knights and the Blades of Dorn Space Marine Chapters against the rebellious Imperial civilised world of Velorum Prime, which had declared their independence from the Imperium. Unwilling to let such behavior go unpunished, these two bellicose Chapters brought the wrath of the Emperor's fury down upon the rebellious Planetary Governor and made him pay dearly for his temerity.

Background
Sometime during the 900s in M30, the civilised world of Velorum Prime was lorded over by the megalomaniacal Planetary Governor Doros Vidius, who ruled the planet with an iron fist. He led a violent and cruel regime, and often exercised his sadistic tendencies on those that displeased. Many Imperial scholars believe that the Vidius' behaviour was the result of daemonic possession or that he was a willing follower of the Dark Gods. Shortly after he rose to power through various nefarious means (such as extortion and murder) he declared his world's indepence from the 'tyrannical rule' of the False Emperor and personally insulted the Master of Mankind. He also (allegedly) sacrificed thousands of Imperial officials to his patron daemon. The actions of such a disreputable individual could not stand.

In response, the local Segmentum Imperial High Command send several detachments of elite Tempestus Scions to quell the world-wide uprisings, but became bogged down in the deadly urban warfare fought within the planet's vast mega-city sprawls, which had been preparing for several years for just such a response from the Imperium. The conflict quickly bogged down into a stalemate, as both sides became deadlocked in a conflict that saw no end in sight. After nearly five years, the High Lords of Terra decided that enough was enough, and so, they sent official orders to both the Tempest Knights and the Blades of Dorn Chapters to help bring the ongoing conflict to a decisive conclusion.

When word reached both the Tempest Knights and the Blades of Dorn of Vidius' cruelty and heretical practices, both Chapters immediately mobilised for war, intent on crushing the rebellious Planetary Governor's rebellion. When both Chapters arrived in-system, they immediately held a war council to decide on how best to proceed. Both Chapter Masters expressed their desire of having the honour of personally slaying the heretic governor, and discussed their plans until they both came to an accord. Since the Tempest Knights were the senior Chapter, the Blades acquiesced, and agreed to grant the venerable Chapter the honour of leading the assault on the governor's palace. By dawn the following day, the Tempest Knights launched an orbital assault on the heavily fortified capital.

Meanwhile, both Chapters teleported their elite 1st Company formations directly into the heart of the palace itself, while the rebellious planetary forces were distracted by the Tempest Knights' initial orbital assault. The Terminator-armoured elite cracked open the supposedly "unassailable" palace and proceeded to massacre the governor's rebellious forces. Outmatched and outgunned, the mortal soldiers were slaughtered in a hail of assault cannon and storm bolter fire and slashing lightning claws. Fighting their way to the governor's command bunker, the Veteran Marines slaughtered all those that opposed them, and broke their way inside, past the bunker's formidable defences. Once inside, the Chapter Master of the Tempest Knights personally slew the heretic governor and took as his head as a grisly trophy. After flensing the head of slain governor and dipping it in gold, he sent the gruesome trophy by Space Marine envoy to the Segmentum High Command. Upon the gleaming surface of the brilliantly shining gold-plated skull were etched the Tempest Knights Chapter Master's words, "Thus, perish all traitors to the Emperor."