Why mauve and white ?

Even today it remains a guess for the reason which caused Charles Roos, founder/chairman of Sporting Club Anderlecht, to pick the colours purple & white.
In the book written by former sports-journalist Max Well on the occasion of Sporting's 50th anniversary, he mentioned that princess Elisabeth was present on a flower parade in Anderlecht and that she was driven around in a coach decorated with purple and white orchids, which match her dress perfectly. Did the queen's dress work inspiring or was it, on the contrary the clergy which played a decisive role ?
Other sources point towards the church garment in which purple and white indeed played a predominant role too. It possibly wasn't a coincidence that in 1908, Sporting played it's very first match against the institute Saint-Georges.
It's an open secret that another Catholic institute from Anderlecht, Saint-Nicolas, transferred several of it's best student-footballers to the Astrid Park. The best-known of them was no one less than Paul Van Himst.

