The earliest known traverse of all fourteen peaks dates back to 1919 when Eustace Thomas led a Rucksack Club group. Thomas Firbank did much to capture the imagination of the wider public with his book I bought a mountain published in 1940.
Your 14 Peaks Stories
14 Peaks Certificate
Snowdonia-Active hosts this public database of known traverses of the fourteen three thousand feet peaks. You are welcome to search the database or to certify the details of a traverse known to you.