Complex sentence: The Albanenses were a group of Manichaeans who lived in Albania, probably about the eighth century, but concerning whom little is known, except that they were one of the numerous sects through which the original Manichaeism continued to flourish.
Split into simpler sentences: The Albanenses were a group of Manichaeans who lived in Albania, probably about the eighth century. Little is known about them, except that they were one of the numerous sects through which the original Manichaeism continued to flourish.