Published in German as: Mysteriengestaltungen, GA 232.
Reedited as: Mystery Knowledge and Mystery Centres.
Given in Dornach on the 7th of December 1923 by Rudolf Steiner.
http://wn.rsarchive.org/Lectures/GA232/English/GC1985/19231209p01.html
http://www.rudolfsteineraudio.com/mysterycenters1923/9mysterycenters1923.mp3
http://en.wikipedia.org/wiki/Johannes_Valentinus_Andreae
http://en.wikipedia.org/wiki/Celtic_Christianity
http://en.wikipedia.org/wiki/The_Book_of_Kells