[NB The brief explanation given below has been drafted on the assumption that the reader is already familiar with the basic building-blocks used in Celtic topographical place-names (Chapter 1 of the Home menu), with the structure of compound place-names (Chapter 2) and with the structure of Celtic river-names (Chapter 19)]
This tribal name is apparently referred to only in the Geography of Ptolemy.
The Epidi were not the people who used the hill-letter l1 appearing at the beginning of Lemandonion (Lemannonius in Ptolemy) and Longus (a place name transferred to a river and listed as the river Longus by Ptolemy), but the earlier people who used the hill-letter n2 present in both place-names. The tribal centre of the Epidi will thus have had a name such as Ebindion, where the element bind means ‘high hill summit’. The hill-letter will have been dropped from Ebindion (cf. Dercandae → Decantae and Vancomagi → Vacomagi) and the b changed to p (this change is known – see Alphabetical List/Changes in names over time, 3) to yield the modified place-name Epidion, the people then being known as the Epidi. Ptolemy indicates that the Epidi lived near the Epidium promontory, which is usually taken to have been the Mull of Kintyre. Note that the hill-letter n2 is used in the old-style manner in Ebindion and Lemandonion, thus used prior to 130BC, but in the inversion-type manner in Longus, thus after 120BC. This suggests that the Epidi had an early tribal centre called Ebindion in the southeast of this region, perhaps on the Cowal peninsula, and that they expanded north and west after 120BC. They will then have founded a new tribal centre at Dunadd (NGR: NR 837 936), just north of the Crinan canal, this new tribal centre having a name somewhat of the form Denconion, where Denc means ‘summit of hill steep’. At a later date that new tribal centre will have been taken over by the Caledoni, who used the hill-letter l1, the place-name then becoming Lodenconion. This form, with deletion of de, the common change c→g and modification of the ending, yields the place-name Longus, which Ptolemy applied to the river now called the Add. The Caledoni of course would apply their own river-letter t to the river and this t, changed to dd, is present in the name Add (cf. Duddon and Nidd). It would thus appear that at one time the Epidi occupied territory extending all the way from Dunadd over to Arran (Lemandonion is identified on this website as the hillfort at Clauchlands, high above Lamlash bay on Arran) but that at some point they were simply absorbed, taken over, by the Caledoni.
[This page was last modified on 16 May 2021]