For many thousands of years, this wild and rugged region of north Wales has been known to its inhabitants as Eryri, 'the abode of eagles'. However, Welsh scholars have more recently proposed a different interpretation and regard Eryri as 'the high land'.

The earliest mention of the name in literature is found in a manuscript believed to have been written by the Welshman Nynniaw, or Nennius.

In it we are told that King Gwrtheryn, also known to us as Vortigern, whilst seeking a safe retreat from the attacks of the English, came to the country called Gwynedd and found there in the mountains of Eryri a place which was fitted for his purpose and which he proceeded to fortify.

There seems to have been good reason for giving this name of Eryri to the Snowdonia area as eagles have inhabited its cliffs and cwms for as long as we know and have furnished bard and storyteller with many an image.

Giraldus Cambrensis mentions the eagle of Snowdon, which perched every Thursday on a certain 'stone of destiny', in the hope that it could feed off the carcasses of men killed in battle.

The place was evidently on the boundary between two cantrefs, where conflict often took place, though not with the weekly regularity that the bird expected - hence the saying that the eagle knows the place, but not the time, at which to find its prey.

In the Elizabethan age, Thomas Price of Plas Iolyn sent a Snowdonian eagle on an errand to his brother poets, and his description of the "king of mountain fowl", dwelling on the "clear-cut heights above the rockbound tarn", makes it certain that he drew his description from actual sightings.

Fifty or so years later Thomas Johnson, the botanist, claimed the reason he failed in 1639 to get the rare plants he desired from the precipices of Carnedd Llywelyn, was that the small boy who was acting as his guide was "too much afraid of the eagles" to take him there.

And in 1802, William Williams of Llandegai noted that "some wandering eagles are now and then in these times seen skulking in the precipices", but in the last 100 years or so, no further sightings have been recorded.

The English had their own name for this region, they called it Snowdon the mountain of snow. Camden, in his original edition of Britannia (1586), uses the expression historicis Latinis Snaudonia, though he was mistaken in supposing that the snow lay on the summits all year round because it was, and still is, a fairly common sight only during the winter months from October to April. Though in very cold years, remnants of drifts may even be found on the north face of the Carneddau well into June.

To add further confusion, 'Snowdon', as used by the older writers, invariably stood for the whole mountainous area which we now call Snowdonia, and never for the single summit to which the name is now restricted.

In the Anglo-Saxon Chronicle, one of the earliest instances of the use of the name says that in 1095 William Rufus came with his armies to 'Snawdun', and in 1188, Giraldus Cambrensis who was familiar with the Welsh Eryri, gives the English equivalent as 'Snaudune'.

In 1230, Llywelyn the Great assumed the new title Princeps Aberfraw Dominus Snawdon, and it was obvious that he was not claiming dominion over a single peak, but as ruler of the whole region which in the Mabinogion is called the "strength of Gwynedd".

Snowdon is now accepted as the modern form of the Anglo Saxon 'Snawdune', supposed to be a literal translation of Creigiau'r Eira, a mistaken rendering of Creigiau Eryri, the 'rocks of eagles'.

This extract from The Complete Guide to Snowdon by Robert Jones, Seren Books, £9.99, is published courtesy of the author.