The Celts originally were from Indo-European stock, arising around Russia c.1000 BC. They came into Europe from the east and settled in central Europe and referred to themselves as "Keltoi" from the greek meaning barbarian. (There is no soft "C" sound in greek hence Celtic etc. should be pronounced with a hard "K" sound. The only exceptions are the pronouncation of sports teams such as Glasgow Celtic and Boston Celtic since the British Empire wanted to distinguish British Latin from other Latin and made one of the differences the use of the soft "C".) Modern scholars divide Celtic culture into two parts named after the areas where Celtic civilisations have been uncovered. The earliest is known as the Halstatt Culture found near Salzkammergut in Austria. They were a warrior race, but were known to the Greeks also as wealthy traders. The Greek writer Euphorus describes them as one of the 4 "great peoples", the others being the Scythions, Persians and Lybians. In 540 BC the Greeks lost their fight against the Corthiginians for control of the Meditteranean and the Celtic culture changed direction.
The later La Tene Culture found near Lake Neuchatel in Switzerland marked another impetus in expansion, trade and war. The Celts probably found their way into Scotland and the rest of the British Isles around 500 BC, but also moved south into the Po Valley displacing the Etruscans. When the Etruscans asked the Romans for help the Celts assumed that the Romans were also a great race and thus began trade with Rome. However, the Roman envoys began to assist the Etruscans in their struggle and the Celts marched on Rome. In 387 BC, Rome was sacked and Brennus, the Celtic leader, demanded his weight in gold.
By this time the Celts had already conquered France by the Celtic tribe Galli; Belgium by the Celtic tribe Belgae; Spain, the Balkans and Turkey by the Galatians. Yet such dominance was short-lived and in 225 BC the Romans had defeated the Celts at the Battle of Telernon. One by one the Celtic nations fell to the Romans, leaving only the British Isles remaining. After the Roman invasion of Britain and the later massacre of the druids in Anglesey that, too, seemed a dying culture. But the Romans never completely defeated Scotland or Ireland, nor the language of the Britons - and the Celtic legacy is still strong today.
The Celtic languages today are split into two camps: P-Celtic is the old Briton, similar to Welsh, also Cornish and Breton. Q-Celtic is Scots Gaelic, Manx and Irish Gaelic. These countries: Scotland, Ireland and Wales, together with the regions of Cornwall, the Isle of Man and Brittany are regarded as the Celtic heartland, although some include England and northern Spain into this amalgam.
In Drumchapel, the history of the Celts can be traced by the Knapper's henge; a druid temple discovered in the 1930s around the site of the Goals Five-a-side football complex. Not all Celtic races would have druids: there is no record of a druid with the warrior leader Brennus, for example, nor any associated with the Belgae. It was only in the British Isles and France that druidism evolved, other Celtic areas may have been too busy warring with their enemies to have this caste system in place.