Strabo Geography 10.2.8

[8] In early times Leucas was a peninsula of Acarnania, but the poet calls it “shore of the mainland,” ¹ using the term “mainland” for the country which is situated across from Ithaca and Cephallenia; and this country is Acarnania. And therefore, when he says, “shore of the mainland,” one should take it to mean “shore of Acarnania.” And to Leucas also belonged, not only Nericus, which Laertes says he took ² but also the cities which Homer names in the Catalogue ³ But the Corinthians sent by Cypselus ⁴ and Gorgus took possession of this shore and also advanced as far as the Ambracian Gulf; and both Ambracia and Anactorium were colonized at this time; and the Corinthians dug a canal through the isthmus of the peninsula and made Leucas an island; and they transferred Nericus to the place which, though once an isthmus, is now a strait spanned by a bridge, and they changed its name to Leucas, which was named, as I think, after Leucatas; for Leucatas is a rock of white ⁵ color jutting out from Leucas into the sea and towards Cephallenia and therefore it took its name from its color.

[8] This was, anciently, a peninsula belonging to the territory of the Acarnanians. The poet calls it the coast of Epirus, meaning by Epirus the country on the other side of Ithaca, ¹ and Cephallenia, ² which country is Acarnania; so that by the words of the poet, we must understand the coast of Acarnania.

To Leucas also belonged Neritus, which Laertes said he took— and the cities which he mentions in the Catalogue,

and they who inhabited Crocyleia, and the rugged Aegilips. ⁴

Il. ii. 633. But the Corinthians who were despatched by Cypselus and Gorgus, obtained possession of this coast, and advanced as far as the Ambracian Gulf. Ambracia and Anactorium were both founded. They cut through the isthmus of the peninsula, converted Leucas into an island, transferred Neritus to the spot, which was once an isthmus, but is now a channel connected with the land by a bridge, and changed the name to Leucas from Leucatas, as I suppose, which is a white rock, projecting from Leucas into the sea towards Cephallenia, so that it might take its name from this circumstance.