An entire library could be filled with the stories of the legendary Victrix Astartes. The following is a very brief summary of this, the "first" Chapter in the sector as recorded by the sector Scriptorium and the Adeptus Astartes Bibliotech archives.
It is widely accepted that the chapter known as the Grunjaegers or later, Green Hunters were the first chapter to establish a base of operations in the Agrippa Sector. After a near century long trek across the galaxy in search of the lost Spear of Destiny, the Green Hunters were forced to settle onTrajanus in order to replenish their failing gene seed.
Whereas the stop on Trajanus was originally supposed to be temporary, the chapter never recovered their seed and has since faded from existence. Some say the Green Hunters were disbanded in dishonour, the result of some mysterious tryst with the ruinous powers. Others say they have taken up their crusade once again and have left on crystal star ships in search of the legendary Spear of Destiny.