All of that inbreeding and not one banjo player in the bunch.
Well played HGC!
And the projected stats from above are too low. Recalling that there is a great deal of Uncle to niece marriage will increase the DNA match from cousins (12.5%) up to 25% automatically.
After 1400 years of inbreeding the first-cousin DNA match must be automatically at 25% and it all escalates higher. In fact siblings from incestual (Uncle/Niece) are already at 25% and their offspring - siblings would breed in excess of 50% DNA similarity.
It’s another reason they have so many kids, many will not survive infancy due to genetic defect..