When were the ring pommels so typical of Irish swords primarily used? Many people describe them as early medieval as if that's proven fact, though the period iconography seems to show them existing mainly in the 16th century as far as I can tell.

Hi Bill. AFAIK all of the surviving ring pommelled swords have come from river finds, this of course makes dating near impossible. As far as surviving artwork goes the earliest example is dated to 1521, while the latest dates to around 1575. However the later example is quite possibly based on an earlier work from the 1540s. So we have evidence for ring pommels in the first half of the 16th century, other than that all we can do is speculate.