> Can anyone tell me what archaeological or other evidence there might be
> that Picts ever settled in Ireland?
Complicated question. When the Gaels settled in Ireland there were
two other identifiable people, the Erin (?pre-Celtic natives) and the
Cruithni (pronounced "croonie, = Pretani = Britani = Britons). The
Erin and Cruithne were finally conquered by the Ui Neill around the
7/8th century. Several generations after this, Irish chroniclers
started referring to the people of northern Britain as "Cruithne"
which has confused a lot of people into thinking the Picts were of
the same stock of, or descended from, the Irish Cruithni. However,
all Irish record contemporay with the Cruithni always call the Picts
"Picti" - quite distinct. The confusion probably arose because in
Irish myth the founder of the Pictish nation was named "Cruithne",
and the Scotti, who moved to Scotland, were also considered
"Cruithni" by the Irish Gaels. So in short, no the Picts did not
settle in Ireland!
> Also, who exactly were Britons? I think the Britons Caesar encounted
> 'became' the modern Welsh, but what area did they cover in his time? Were
> they throughout the British Isles? The whole of England? Only southern
As far as is known the Britons were the Brythonic-speaking Celts who
were pretty well over the whole of Britain, Man, and had even started
to colonise Ireland. British Celtic is related to, but slightly
different from, Gaulish Celtic, though quite a few Gallic tribes
straddled the Channel at the time of the Roman invasion.