Complex sentence: There is a longstanding tradition of excellence in musicals, going back to the earliest days of the school under Sister Francis O.P. The most recent of these has been Les Misérables School Edition performed in January 2008.
Split into simpler sentences: There is a longstanding tradition of excellence in musicals. Stemming back to the earliest days of the school under Sister Francis O.P., the most recent of these has been Les Misérables in January 2008.