The records for St John's College, Cambridge where Morgan was a student show that he was born at Nethey, Radnorshire, son of John. Tithe records show that John Lewis of Neu Addu (which would be pronounced as something resembling Nethey) was the landowner and occupier of some 20 fields around Neu Addu. This is now shown on Ordnance Survey maps as Neuaddu-ddu about 3 miles south of Llangurig on the A470. Although some 4½ miles from the village of St Harmon it is (just) within the Parish of St Harmon.

There are many baptisms of John Lewis around the right time but none close enough to the Saint Harmon area to be confident of having found the right one.