Complex sentence: The two theatres, both owned by Sefton Parry, were built back to back, known therefore as the "Rickety Twins" and were built on the site of the former Lyon's Inn, an old Inn of Chancery, previously belonging to the Inner Temple.
Split into simpler sentences: The two theatres, both owned by Sefton Parry, were built back to back, and were known as the "Rickety Twins". The theatres were built on the site of the former Lyon's Inn, an old Inn of Chancery, previously belonging to the Inner Temple.