In ancient times in Orini Nafpaktia lived the Apodoti, descendants of the Aetolians. Their capital was Aigitio which was located in a mountainous area at the foot of Korakas (western peak of Kerasovouni). According to the prevailing version, Aigitio was located in the SE. of today’s Elatou, in the area of Paliochoria and the place Koskina where remains of art foundations of irregular Greek were found.
Remains of carved stones of ancient tombs were found at Mnimata. According to Thucydides, in 426 BC. Aegitio was conquered by the Athenian general Demosthenes in an attempt by the Athenians to defeat the Apodotes who were the main force of the Aetolians and then to subdue the entire Aetolian tribe, whom they characterized as warlike and dangerous. Eventually, however, the Apodotes, aided by the Ophionians (who also belonged to the Aetolians), with repeated attacks defeated the Athenians and forced them to leave the area.
From the 3rd AD century Aitoloakarnania receives a wave of raids and barbaric attacks.
Of particular importance is the invasion of the mountainous Nafpaktia of Huns of Serbian origin from 1059-1069. They settled permanently in the area practicing the profession of shepherd (goat shepherd) and founded settlements with Slavic names and toponyms. Slavs also settled in Elatou, and the name of the village Eletsou or Eletzou was Slavic and meant “sunshine”. In the village many place names such as Pleika, Reseika, Gidio, Chok etc. are of Slavic origin. The Slavs quickly left the area but the toponyms remained.
During the Frankish rule, the mountainous Nafpaktia was subordinate to the Venetians but was not occupied militarily due to the remote and inaccessible area and the disobedience of its inhabitants. In 1499 the whole of Aetolia passed into the hands of the Turks. From 1687 to 1699 it fell again to the Venetians and so the mountainous Nafpaktia was considered almost free since the Venetians did not disturb it. However, from 1699, with the treaty of Karlovic, the Venetians ceded to the Turks the area of mountainous Nafpaktia called Kravara, to which Eletsu also belonged.
In 1820 Turkalvans who were expelled by the guard of Nafpaktos took refuge in mountainous Nafpaktia where they committed looting. They set fire and Eletsou was burned. At that time there were 20 families in the village who to save themselves took refuge in a cave outside the village called “Bear Holes”. After the fire, 17 families remained in the village and decided to rebuild it on the site of present-day Elatou because the ground in this area was firmer than in Paleochoria.
In 1833, when the new administrative division of the country took place, Eletsou became part of the municipality of Apodotia in the province of Nafpaktia. Because almost all the villages in the area of mountainous Nafpaktia had Slavic names, from the time when the Slavs had settled in them, from 1921 to 1928 the villages were renamed with Greek names and Eletsou became Elatou thanks to the fir forests that surround it.