The Celts built fortifications of massive proportions on hill-tops, such as Maiden Castle in Dorset, but they were for the defence of a community against the Roman Legions, mainly (as the Picts, who were probably Celtic, did with their brochs), and also against their neighbors -- these folk were very warlike, and had already subjugated the native population of Britain, the ones who built Stonehenge, for example, into slavery (in places like Ireland, where they had done the same thing, they called the old folk Firbolgs and Little People). People of Celtic ancestry should always keep this in mind, that they were invaders from central Europe, and that they were NOT the native population of the British Isles (who were more like the Basques and folk like that where they have survived). Places like Camelot did actually exist during the Dark Ages -- they were defenses against the Saxons, other invaders, and rival Celtic dynasties -- but nothing like the glorious castles of Medieval Arthurian romance.
Castles by their very nature are points of subjugation and suppression.
They look marvelous to us nowadays, but they were centers of tyranny in their time,
which is why so many were broken to ruin when Cromwell destroyed the old feudal hierarchy,
and after that most of them fell into disuse and were plundered by local farmers for
convenient building material. Preservation of old buildings is a big business now, but you can
see why nobody cared about the old castles once their threat was gone (except for the ones
they converted to prisons). Welsh Castles are one of the earliest manifestations of "British
Imperialism" as started by the Normans, who as a people should be blamed for the whole
idea and implementation of that policy. The castles of Wales and Ireland, Brittany, Cornwall
and Mann, and a lot of Scotland for the most part all fall into this category. Some of the
native princes of Wales and Scotland built their own castles (in remote places) in imitation
of their oppressors. (Such as the so-called native Welsh castles of the last princes of Wales before the upstarts.) The Scottish, Irish and Northern English tower house, and its later
development, the baronial castle/hunting lodge (see Lauriston, for example), were a later development and were based
on historical conditions, not on "celticism" or anything of that sort
(except in the sense that they were family/tribal cores when there was no
so-called central government, and later on became displays of clan pride,
which IS a Celtic characteristic -- although it never reached the level of
Ludwig of Bavaria).
But given that the Celts bullied the European world before Caesar, in turn they
were subject to Germanic impositions -- note that Germanic peoples are not
a DIFFERENT RACE of humanity, the difference is just in cultural roots
and language family. Language is more likely to influence race than the other
way around -- your vocabulary defines your behavior, the precision of German as opposed to the lyricisim of Welsh.
(A virtue of a hybrid language like modern English is
that it can be spoken either way using the internal translation mechanism of
the speaker of another language -- it is well adapted to that and has none of the
aggravating stuff about genders and declensions, all of that nonsense having been
purged away by centuries of suppression by the Normans. Old Anglo-Saxon was just
as bad as German originally in that area. You can also say the same about Welsh
having been trimmed down by suppression -- it might look horrendous with its odd
spelling and have some odd rules of grammar, but it's nothing like the original
Gaullish/British that had rules that were as complicated as Latin.)
In any case, those linquistic and cultural habits pervade these ethnic variations to this very day in spite of the so-called 'races' having little distinction after all these
years of intermingling. Any cliches
about wild red-headed Irishmen, etc. are total nonsense, it's all a matter of
red-headedness as a genetic trait associated with hot tempers and impulsiveness (such as my wayward irresponsible sister
-- sorry, Vickie). If Celtic men are predisposed to cut up in bars, that is a matter
of cultural nurture, not of some racial characteristic. Drunkenness is a feature of
ALL northern European societies: they were never subject to Muslim domination,
and besides, what are you going to do during the long and gloomy winters?
(You also have to give the Celts credit for inventing the whisky still, since obviously
wine is not something you can make very well in northern climes -- you've got to hand
it to these people for that major advance in technology, otherwise we wouldn't have
gasoline -- Jesse Jackson or Al Sharpton cannot claim this was invented in Africa,
although many people would have preferred hard booze had never been invented at
all. Whisky ranks as one of the major contributions of the Celts to world-wide
culture.)