Ancient Greeks knew them as Keltai and later as Galatai both probably deriving from Celtic tribal names.
The Latin equivalents were Celtae and Gallus.
The Celtic (or Gaelic) languages are part of the larger Indo-European family of languages and as such related to Greek, Latin, German, English etc.
Origin of the Celts in Ireland
Earlier historiography believed the Celts had invaded Ireland from the continent sometime in the first millennium BC.
Recent research suggests that the introduction of Celtic culture and language was gradual and continuous. At any rate, Celtic languages and culture seem to have been well entrenched in Ireland and Britain before 500 BC.
History of the Celts - Celtic Kingdoms
In Ireland, Celtic tribes established a number of kingdoms. One of the earliest in what is now Northern Ireland were the Volunti or Ulaid.
They are mentioned in Ptolemy's 2nd century BC Geographia. Their capital was probably in Navan Fort (Eamhain Mhacha), County Armagh.
There is an interesting Visitor's Centre in Navan Fort, well worth a visit.
At their greatest extent the Volunti ruled all the way south to the river Boyne and west as far as county Leitrim.
Navan was destroyed in the 4th century AD and th Volunti kingdom
came to an end.
Other early Irish kingdoms were the Erdini in County Fermanagh and the Robogdii in County Antrim and Londonderry.
The best known Celtic Kingdom
Perhaps the best known kingdom was Dalriada. Originating in Antrim, at its height in the 6th and 7th centuries AD it covered a large part of south-western Scotland and what is today County Antrim in Northern Ireland.
The kingdom disappeared by the time of the Viking invasions.
Perhaps Dalriada' greatest claim to fame is its association with Saint Columba who was instrumental in spreading Christianity to northern Britain.
The famous book of Kells may well have been produced by Dalriadan monks.
Celts were organised tribally. At the head of the tribe was the king.
Society was divided into three classes:
the warrior aristocracy
the intellectuals composed of druids, poets, etc.
and everyone else
Women were known for their beauty and there is some evidence where they could wield substantial authority (nothing strange here!).
There is both literary and archaeological confirmation that some women became warriors.
Warfare was common. The soldiers carried a long sword and sometimes a round or hexagonal shield.
Trading was common and abundant among the Celtic tribes with an ancient system
of roads transversing the areas of occupation of the main tribes.
Lastly, they wore a long sleeved shirts and trousers which the Romans called braccae.
Wow, I learned a lot, did you?
Enjoy the sights of the Emerald Isle. The background music is from Enya The Celts.
Information on the clips: (I will add more to this list soon).
The Book with the illustrations, is the famous Book of Kells.