Board Thread:Warhammer 40k General Discussion/@comment-25618639-20150604030859/@comment-8881468-20150811053251

to quote the Lorgar article

[quote]" When the infant Lorgar fell from the sky, his Legion had yet to be born on Terra, and the faith of Colchis was held in the hands of a ruling priesthood called the Covenant. Discovered by the followers of this predominant religion on Colchis, the Covenant, later known as the Old Faith or the Old Ways, was a polytheistic religion dedicated to the worship of entities that were in fact the Chaos Gods in more benevolent guises, and Lorgar was raised amongst this priesthood. Studying within a temple of the Covenant, Lorgar quickly became a devout preacher, his skill in oratory and the power of his charisma winning him many followers.[/quote]

aka: he was a preacher of chaos while growing up.