Names such as Billy Bankcroft and Haydn Tanner make up part of the list but it is a man called Norman Biggs who Prydie will replace at the top of the list.
Biggs became the youngest player to don the Welsh jersey when he made his debut against the New Zealand Natives at the age of 18 years and 50 days on 22 December, 1888 - 104 years before Prydie was born.
It proved to be a winning start to an eight cap career that reached a crescendo in 1893 when he scored two tries in Wales' first Triple Crown season, by which time he was 22.
The son of a brewer in Cardiff and Bath, Biggs captained both clubs and was one of six brothers who played for Cardiff. In fact, a Biggs played for the Cardiff 1st XV for 22 consecutive seasons.
Norman also played cricket for Glamorgan alongside his brother Selwyn, who won nine Welsh caps.
And a poignant illustration of just how different life in the last century was the demise of the man. Biggs served as a private in the Glamorgan Yeomanry in the Boer War and was a Superintendent in the Nigerian Police when he was killed by a poisoned arrow during a native ambush in Sakaba, Nigeria in February, 1908. He was 37.
It was more common to earn a cap whilst still a teenager in the 19th century. In fact, nine of the 14 18 year olds won there first cap in that era. Only one player in the post war era, Keith Jarrett, makes the list.
Recent high profile players to make Wales debuts are Gavin Henson, (19 in 2001 against Japan) and Leigh Halfpenny (19 in 2008 against South Africa).
Wales' 18 Year Old Caps
Tom Prydie v Italy 2010, 18 yrs 27 days
Norman Biggs v New Zealand Natives, 1888 18 yrs 50 days
Evan Williams v England, 1925 18 yrs 213 days
Harry Bowen v England 1882 18 yrs 226 days
Tom Pearson v England 1891 18 yrs 238 days
Lewis Jones v England, 1950 18 yrs 285 days
Will H Thomas v Scotland, 1885 18 yrs 294 days
Keith Jarrett v England, 1967 18 yrs 332 days
Edward Treharne v England, 1881 18 yrs 334 days
Billy Bancroft v Scotland, 1890 18 yrs 336 days
Haydn Tanner v New Zealand, 1935 18 yrs 346 days
Frank Hill v Scotland, 1885 18 yrs 363 days
The birth dates for the following players have never been established, but they were 18 when they made their debuts:
Bob Gould v Ireland, 1882
Llewellyn Lloyd v Ireland 1896