The 1st Coy. was completely wiped out during the assasination of Lannes at the Battle of Fladgate City, an event steeped in controversy. Popular consipiracy claims that a Chaos infiltrator within the ranks of the Victrix Astartes played a direct role in the fall of the 1st Coy.
These rumours have been enough to have seen the entire chapter disappear in late M41. Some say the chapter has been excommunicated while others maintain the shame of losing the Green Knights led to self-exile.