The Areth are a people inhabiting the continents of Arophania and Marcasia, and whose country, Arithia, spans the two. While not all Areth live within the borders of modern-day Arithia and not all Arithians are ethnically Areth, the concept of Areth nationhood has always been closely tied to that of an Arithide state.
The name Areth, while in common use even among the Areth, is not autonymous, instead being of Dethric origin. The name arose on contact with the exploratory delegations of the Lazeian Empire during the Agia Dynasty, which first arrived in Dethria in 260 BCE (Agia 65). It is said that due to differences in language, when the Dethrians approached the party that had disembarked from the fevouns, enquired about their provenance and gleaned the reply that they had come from the "venerable realm of the Agia" (ō alēmir lisogāros Agiarēthir), all they could remember were the last three syllables arēthir, whence derived the appellation. While the anecdote is most probably apocryphal, ethnologists consider the name Areth almost certainly to have been derived from Agiarēthir.
The Areth of old called themselves the iounai (sing. ither), literally meaning "the I people". While it is as yet unclear regarding the origin of the name, the word gradually evolved two plurals, one being the original irregular iounai, and the other the regularisation ethirai. Ither has undergone a semantic broadening, catalysed by contact with the Dethrians, and its modern guise, iter, means simply "person" today. While the fossilised regular classical plural ethirai also broadened to mean "peoples" as a collective noun, iounai shifted with the rise of nationalism to denote the Areth as a whole nation, ethnically speaking.
- Main article: History of Arithia
Due to the ambiguity of archaeological evidence, the origins of the Areth are shrouded in doubt, and while the Marcasian Theory of Origin has gained widespread currency both in academic circles and among the general public, much of it relies on inference, deduction and intelligent hypothesis to fill in the gaps left by archaeology, or the deficiencies thereof.
According to the Marcasian Theory, the Areth first arose as a distinctive ethnicity (Arithide: kyteos) as the sedentary, agricultural Erda culture along the lower reaches and delta of the river Or, more than 6,000 years ago. The Erda were in turn descended ultimately from the hunter-gatherers who had settled in southwest Marcasia approximately 67,000 years ago. Hemmed in by the Chisthian Sea and the Iryagi, the Erda peoples faced, from the beginning, very visible limits to the the land and its fertility, and such persistent population pressures led to successive waves of emigration, some northwards over the Iryagi into the Marcasian interior, but most were headed south across the Chisthian, the easier route by far for a fishing people. This so-called Southerly Movement, by which the Areth came to settle in northeastern Arophania, was once thought to have emptied their homeland in Erdia and attritionally established the settlements of the Nuroi, Pisa and Duvai cultures along the way, but is now considered to have left a minority behind, who fled a flooding of the Or to establish the mentioned three successor cultures..