Ierne is fairly obviously a mispronunciation of 'Er Inis' or 'Eire Innis' (various spellings are available), meaning 'West Island' in common Celtic. The name remains in use today in its full form - Eireann.

(Additional information by Edward Dawson, and from Marie Mc Keown, Hub Pages.) Until now a land bridge has connected Britain to Ireland, roughly from the south-eastern tip of the latter to south-western England.

The most striking feature of pre-Ptolemy Ireland are legends of the island being divided in half between north and south.

At some point after about 500 BC, there were certainly arrivals by Indo-European Celts (and perhaps even as early as 2000 BC), and they remained fully independent as Ireland was never conquered by the Romans.

Instead the Celto-Irish helped to hasten the end of Roman control over Britain by constantly raiding the British coastline, capturing slaves and booty.

Then in the late fourth century, Niall of the Nine Hostages apparently dominated much of Ireland.

His offspring, the U Neill, used a descent system to describe themselves, and this appears to have been adopted by most of the island.

The later high kings were nominally in charge but in practice, descended as many were from the prominent U Neill clan, there were always stresses and strains with the other regions.

For the earlier high kings, the title was more of a ceremonial one, and never implied political control of the whole country.

The last holdout may have been the Fir Domnann (the Dumnonii Men), possibly one of several British tribes who saw fragments of their number move to Ireland.

Coverage here of the Irish tribes therefore is a snapshot, figuratively taken by Ptolemy.

By this time, Cairn G, one of a cluster around Carrowkeel in the Bricklieve mountains, has been erected.

Carefully set into the entrance of Cairn G is a hole that is positioned to let the sun's rays into the inner chamber for a month either side of midsummer, with possible extra use for the moon's rays at midwinter.

One of those captured slaves helped to convert the Irish to Christianity - the Romano-British Saint Patrick in the mid-fifth century AD.