Jim, the temple is called Preah Palilay and is believed to date from 12th or 13th century. It's tucked away in the northern corner of Angkor Thom and is generally not visited by most tourists, unless they have hired a proper guide and have lots of time (there is so much else to see). I just stumbled upon it while wandering the grounds of Angkor Thom. Regards, -Najinsky