This is Sir Taran ap Deiniol (my son) wearing a full coif and tunic of crocheted mail. The ‘ap’ in his name means ‘son of’ for the Welsh. If he were a girl, the ‘ap’ would become ‘ferch’, meaning ‘daughter of”.
Among the Welsh today, the number of surnames are few. In general, if you encounter someone with a first name as a last name, their ancestry may very well be Welsh. In Wales today, Jones, Davies, Evans, Williams, and Thomas are the most common surnames. http://www.genealogymagazine.com/welsh.html
The reason for this was that the Welsh adopted the use of true surnames very late–beginning in the 15th century and the process didn’t finish until the 18th. This meant that 1) the use of English names and the Englishization of Wales had fully taken hold and 2) the Church’s use of English baptismal names was well-established.
Thus, among the Welsh, instead of having names based in a person’s place, occupation, personal nickname, or place of origin, names exclusively were rooted in the father’s name.
As Eustace ap Evan writes:
“None of this holds any comfort for the genealogical searcher in Wales. Seekers after the more-common surnames are doomed to failure unless they have a great deal more information than “William Thomas from Wales.” And, even with their quarry traced and identified in the 19th Century, sooner or later the parish register entry will appear, which says “Evan son of William Thomas baptized,” and no more. If it is late in the 18th Century, he is likely to be Evan Thomas; if it is early in the century and in a fairly Welsh area, he is probably Evan William. If it is a town or other Anglicized area, he might be Evan Thomas as early as the 17th Century, or, indeed, very much earlier than that.
Towns were English plantations, mainly, and had surnames from their foundation dates — but were prone from the 16th Century onwards to be infiltrated by Welshmen who may not always have adopted town ways at once. Added to this uncertainty is the depressing probability that he is probably far from being the sole possessor of his name in the parish, whichever it may be.
Once the comforting signpost of a surname is left behind, there is very little hope of making further progress except in the case of a relatively wealthy family, who may have left written records of their affairs — wills, at the very least, are needed. The sort of family, that is, who would have adopted a surname and is, in fact, on the point of doing so. Thus, it is often possible to go back a further generation before the surnames. But, to make substantial further progress will be impossible unless, at the same time, a secure connection can be made with one of the many medieval Welsh pedigrees, which have been brought down to the 16th-18th Centuries.” http://www.users.qwest.net/~butchmatt/WelshNames&Surnames.htm