"According to the contemporary *Annales de Theokesberia, the chronicle of Tewkesbury Priory, Joan's mother was named Clemence--a rather unusual name in England at that period, which may suggest that Joan's mother was French.
. Joan was declared legitimate by papal letters of 1223, which make it clear that Joan was born at a time when both John and Joan's mother were single, that is, before 1189 when John married Isabella of Gloucester. This too might point to a continental birth for Joan, as John spent a good deal of time in Normandy and Poitou before Henry II died and John's marriage, coupled with Richard I's beneficence, first gave John substantial English interests. We know, furthermore, that when Joan's marriage to Llywelyn of Wales was arranged in 1204/05, she had to be brought from Normandy to England for her wedding; the order for her expenses on the journey to be paid from the Exchequer exists on the Patent Rolls for John's reign.
It is not easy to find a convincing explanation for Joan's presence in Normandy unless she was born and had grown up there. John was never a doting father to any of his children, including those by his queen, and it is unlikely that he would ever have gone to the trouble of sending Joan to Normandy from England had she been born in the latter.