Celts dominated western Europe in the hellenistic and early roman era. Starting from near the type sites of Hallstat, now in Austria, and La Tene, now in Switzerland, between 800-600 b.c., the Celts spread their culture and language all the way to what are now Spain, northern Italy, eastern Europe, and the British Isles. Celts centered in Italy's Po valley sacked Rome in 387 b.c. At the time Julius Caeser conquered Gaul in the mid first century b.c., the area that was to become modern France was considered to be the gravitational center of a powerful, Europe-wide Celtic culture.
Even then, the celtic interlace style that is still current and familiar to us after two and a half millenia was being practiced, as you can see in the detail from the helmet of Agris, France, a detail from which can be seen in our illustration above and left, dated to the 4th century b.c. Later, roman ladies often bought their fibulae, which were like rather large, decorated, safety pins that they used to pin their cloaks together, from celtic sources and decorated with celtic interlace designs.
Now, naturally many people these days assume that ireland, scotland, wales, and brittany would be the centers of celtic culture, despite what is know to students of the history of celtic culture, and since the only surviving celtic languages are from these areas (we heard quite a bit of welsh on the radio when driving though powys a few years ago). As we said above, the british isles appear to have been conquered by the celts in the middle of the first millenium b.c., and very little is known about the more indigenous cultures of the islands. Except, we should say, for Ireland, where folklore preserves the names of the cultures that preceeded the celts, including the Fir Bolgs, and the Tuatha Dé Danann. (The weapons of the successive waves of Firbolgs, Tuatha de Danann ("People of the Goddess"), and, finally, Celts, are described in the folk histories.)
Logically, then, modern celtic languages bear roughly the same relationship to the Gaulish celtic language of ancient times that modern romance languages do to Latin. So, what was Gaulish like? Fortunately, a number of inscriptions, many (as below) written using basically the greek alphabet and inscribed when the romans had not yet broken out of italy, are available and give us a decent idea of Gaulish.
What we find out is that Gaulish, the ancestor of modern celtic languages, was very close to Latin! It is thought that Latin succeeded Gaulish very easily after it became part of Rome because of this close similarity. A well known example of this similarity is the name of the great warrior who attempted to organise the Gaulish chiefs against Julius Caeser, Vercingetorix, where the "rix" is the Gaulish version of Latin "rex", king. Also, the word "fir" in the name "Fir Bolgs", means "man", and is the Celtic version of Latin "vir".
Possibly, the reason for this close similarity (Gaulish is much closer to Latin than Greek is) might be in a common origin in the Urnfield cultures of the late bronze age central europe. Many scholars postulate that both the Hallstat Celts (the earliest archaeological culture recognizable as definitely celtic) as well as the early romans and their relatives the oscans and umbrians, derive from the migration of the Urnfield peoples from central europe southwards and westwards during the tumultuous period at the end of the bronze age and the beginning of the iron age, 1200 - 900 b.c., sometimes known as the "greek dark ages".
Here is a little table of some common words:
Gaulish--- English--- Latin
-cue------ and------ -que
es--------- out of-------- ex
are-------- before---- ante
ver-------- over------ super
allos------ second---- alius
tarvos---- bull------- taurus
tri--------- three----- tres, tria
more------ sea------- mare
rix--------- king------- rex
lanum---- plain------ planum
I was puzzled when trying to etymologize the medieval name of that ancient celtic settlement, modern Milan, 'Mediolanum'. "Medio-", in the middle of something, but what? "Lanum" - wool? The mystery was solved when I read that in Gaulish, the 'P' was commonly absent at the beginning of words that in Latin would have "pl-". Therefore, Mediolanum would be in Latin Medioplanum, "in the middle of the plain"
Gaulish was also a highly inflected language, as were Latin and Greek.
Most surviving Gaulish is in brief inscriptions, on stone altars, tombstones, jewellry, and coins. Here are a couple of early inscriptions, from the pre-roman period when the greek alphabet was employed:
ϹΕΓΟΜΑΡΟϹ ΟΥΙΛΛΟΝΕΟϹ ΤΟΟΥΤΙΟΥϹ ΝΑΜΑΥϹΑΤΙϹ ΕΙωΡΟΥ ΒΗΛΗ ϹΑΜΙ ϹΟϹΙΝ ΝΕΜΗΤΟΝ
SEGOMAROS OUILLONEOS TOUTIOUS NAMAUSATIS EIOROU VALA SAMI SOSIN NEMETON
"Segomaros, son of Uillo, toutious (tribe leader) of Namausos, dedicated this sanctuary to Belesama"
ΔΟΒΝΟΡΗΔΟ ΓΟΒΑΝΟ ΒΡΕΝΟΔΩΡ ΝΑΝΤΑΡΩΡ
DOVNOREDO GOVANO VRENODOR NANTAROR
(apparently dedicated to Gobannus, the Celtic god of smithcraft)