The Welsh Patronymics project was officially begun on December 6, 2002. The project was designed for the patronymic style surnames (Williams, Jones, and Roberts, just to name a few) which are found in Wales. The reason for this is that the patronymic surname system persisted in Wales much longer than in many other parts of Europe, as recently as 1813 in some areas. What that means is that the son of a man named Robert Williams might have been called Hugh Robert or Hugh Roberts, so did not have Williams as his surname.

Welsh patronymic surnames take on three forms:

1. A masculine name as it is (particularly common for masculine names ending in “s”, though not always that way). Examples: James, Thomas, Lewis, George, Owen, Griffith, Morgan.

2. A masculine name followed by a possessive “s.” Examples: Williams, Jones, Evans, Edwards, Matthews, Roberts, Hughes, Harris (son of Harry), Davies or Davis (son of David/Dafydd).

3. A masculine name beginning with the prefix “ap” or “ab” (the “a” is usually dropped in the modern form). Examples: Powell (ap Howell), Pritchard (ap Richard), Price (ap Rhys), Bowen (ab Owen), Bevan (ab Evan), Pugh (ap Hugh).