What were the original names of Mochdref, Mochtref, Mochnant and Mochtref?

Question

In the fourth branch of the Mabinogion, Gwydion and company move through the areas surrounding the court of Dryfed after receiving pigs from Pryderi:

That night they made it as far as the uplands of Ceredigion - and the place [where they stopped] is still called 'Mochdref' because of that. The next day they went on their way [and] they came through Elenid. That night they were between Keri and Arwystli, in a township that is also called 'Mochtref' for that reason. And thense they went onwards, and that night they came to a commote in Powys which is likewise called 'Mochnant' after that incident, and they were there for the night. And from there they went on as far as the cantref of Rhos, and there they were that night in a town still known as 'Mochtref'.

"Mochdref" literally translates to "Pig town", and "Mochnant" literally translates to "Pig valley".

The same thing later happens at a town thereafter known as Creuwyryon.

What were the original names of the four places thereafter known as Mochdref, Mochtref, Mochnant and Mochtref?

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^{It appears that the name "Mochnant" has survived, indicating that these places may not been simply figments of a tale, but real towns.}

Answer 1

Onomastic tales like this one are common in literature and histories, be it the Middle Ages or Ancient Greece (there are several others in The Mabinogion, as well). Such place-name explanations can involve real or fictitious locales, and often provide rather fanciful rationalizations. In this particular instance, the author (or, perhaps originally, poet) seems to be describing actual places known at the time by those names. Asking what their “original” names were implies that their names were changed because of influence from the tale. However, it’s more likely that these places already had those names, and then the author provided this tale as a way to explain the origins of those names.

(Still, it must be said that the reverse is not impossible, in that one or more of these places might have commonly been known by another name, which subsequently changed because the tale somehow became associated with that place. In this particular case, we simply don’t know.)

Additionally, I can provide you with some information on what the corresponding present-day names of said places might be. Taken from Sioned Davies’ translation of The Mabinogion, in her explanatory notes (pg. 50), she writes,

It is difficult to locate these places with any degree of certainty. The Mochdref in the uplands of Ceredigion may refer to a location to the north-east of Aberystwyth, in the vicinity of today’s Nant-y-moch reservoir. Elenid is in southern Powys, and refers to the mountainous land known as Pumlumon (Plynlimon) today. Ceri and Arwystli … were a commot and cantref respectively, in the area around Newtown and Llanidloes; indeed, about 3 miles south west of Newtown is the parish of Mochdref. The commot of Mochnant was partly in Denbighshire and partly in Montgomeryshire, while the Mochdref in the cantref of Rhos is located between Colwyn Bay and Llandudno.