If this genetic marker is 4,000 years old, then it would have been pre Roman. Was this an area of Wales that could have supplied tin to be alloyed with copper to create the Bronze Age. Perhaps ancient eastern Mediterranean peoples were traveling here by boat to either mine tin, or to trade for tin. An while there, enjoying the local female companionship. They could have had a settlement with extensive mining and commercial activity centered around the importance of the tin trade.
"Roman soldiers in BritainSignificant frequencies of E-V13 have also been observed in towns in Wales, England and Scotland. The old trading town of Abergele on the northern coast of Wales in particular showed 7 out of 18 local people tested were in this lineage (approximately 40%), as reported in Weale et al. (2002). Bird (2007) attributes the overall presence of E-V13 in Great Britain, especially in areas of high frequency, to settlement during the 1st through 4th centuries CE by Roman soldiers from the Balkan peninsula. Bird proposes a connection to the modern region encompassing Kosovo, eastern Serbia, northern Republic of Macedonia and northwestern Bulgaria (a region corresponding to the Roman province of Moesia Superior), which was identified by Peričic et al. (2005) as harboring the highest frequency worldwide of this sub-clade.[Note 11]"