Apocrypha of Skaros

The oldest known surviving copy of the Codex Astartes, frequently copied and cited. It lists the number of Second Founding Ultramarine successor chapters as twenty-three, but does not name them. Other sources do not neccessarily agree with this number. It also lists the number of Second Founding chapters created from the Space Wolves as two. (Source: Index Astartes vol I page 13)