The 88th Siege Army was raised from the planet Krieg to prosecute the Siege ofVraks, the planet having rebelled against the Imperium following the attempted assassination of the Apostate Cardinal Xaphan. It originally consisted of 4 line korps, each consisting of 4 Siege regiments, 2 Assault korps, combining Tank, Siege and Artillery regiments, 2 korps of 3 Siege Artillery Regiments, with 10 Independent Artillery Companies and 4 Heavy Mortar Companies.
Overall command was given to Lord Commander Zuehlke, a son of a noble family.
The first troops arrived in the Vraks system at 199812.M41. The 143rd Siege Regiment was the first to make landfall, and began digging in.
The command for the first volley of fire was issued at 1666813.M41. The siege was expected to last 12 years, but, owing to the intervention of several Chaos Space Marine forces, it dragged on until 830.M41.