Complex sentence: Pontefract was the site of Pontefract Priory, a Cluniac priory founded in 1090 by Robert de Lacy dedicated to St John the Evangelist.
Split into simpler sentences: Pontefract was the site of Pontefract Priory. This Cluniac priory was founded in 1090 by Robert de Lacy, and dedicated to St. John the Evangelist.