The Morrigan and Morgen le Fay

One source of much confusion is the connection - or lack thereof - between the Irish goddess the Morrigan and the Welsh Arthurian figure Morgen le Fay*. I've been meaning to write about this for a while but have hesitated because I am admittedly weak on the Welsh end of things and didn't want to do a disservice to the subject. However I've had several people ask me recently about what connection