Region of north Greece, divided into the four tetradĕs (districts) of Thessaliotis, Hestiaeotis, Pelasgiotis, and Phthiotis. Comprising two vast plains divided by hills, Thessaly is enclosed by mountains (notably Olympus, Ossa, Pelion, Othrys, and Pindus) which are pierced by valleys and passes, by which, in all periods, travellers, merchants, and armies have reached the Thessalian plains. Thessaly has access to the sea only by the gulf of Pagasae. It has a continental climate, with extremely fertile soils; it was rich in grain, horses, and other livestock, although its relative coolness largely precluded cultivation of the vine and olive.
From c.1000 bc Thessalians, from the southern half of the eastern plain, progressively took over more and more land, eventually coming to dominate (over the passage of 1,000 years) the two plains and also the surrounding mountains. The Thessalian ethnos early on formed itself into an organized state, with cities led by aristocratic families and grouped into a federation under the authority of a chief.
Their military power first gave the Thessalians access to the Peneus basin and part of the eastern plain, as well as the southern regions of the Othrys range, the Spercheios valley, and the coasts of the Maliac Gulf; then central Greece. Winning control of the amphictiony formed by the population of these districts and based first at Anthela, then at Delphi, the Thessalians were for a while a dominant power in central Greece. But from c.600 they were forced to fall back on Thessaly proper. In the second half of the 6th cent. the Thessalian state was reorganized by Aleuas the Red, who created the four tetrads each of four cities. Aleuas adapted the territories of each city for military mobilization by creating land‐allotments controlled by officials charged with organizing the state's military units, and thus created an effective army.
In the 5th cent. the Thessalians strengthened their hold on Thessaly as a whole; of the population of the two plains a part was now integrated into the cities (which increased in number), the rest expelled to the mountains. Federal ties weakened following the rise to political and economic dominance over their neighbours of the cities of Larissa, Pherae, and Pharsalus. Urbanization progressed and wealth accumulated; aristocratic families engaged in their rivalries, but also were forced to cede to political pressure from ordinary citizens seeking a say in local government, which became progressively more democratic.
Subjects: Classical Studies — Medieval and Renaissance History (500 to 1500).