Thessaly
2 of the 7 encyclopedias on this shelf carry an entry for Thessaly. Both are reproduced below, so you can see where they agree and where they differ.
Collier's New Encyclopedia (1921)
the largest division of ancient Greece; lay S. of Macedonia and E. of Epirus; being separated from the latter by Mount Pindus, and from the former by the Cambunian Mountains; the Maliac Gulf and Mount Eta bounding it on the S. It is a vast plain shut in on every side by mountains; on the N. and W. by those already named, on the S. by Mount Othrys, and on the E. by Mounts Pelion and Ossa, the only opening being the Vale of Tempe in the N. E., between Ossa and Olympus. This plain is drained chiefly by the Peneus river (now Salambria) and its tributaries, and is the most fertile in all Greece. Thessaly was originally inhabited by socalled Pelasgians, who, however, were either expelled or reduced to slavery by Dorian immigrants from the more rugged region of Epirus about 1000 b. c. The Peneste, descendants of the old inhabitants, held a position analogous to that of the Helots in Sparta. There were four districts-Hestiæotis, Pelasgiotis, Thessaliotis, and Phthiotis; Magnesia the coast being a minor division. The government appears to have been oligarchial in the separate cities of which Pharsalus, Larissa, Heracleum, and Phere were the principal-power being in the hands of two great families. About 374 b. c. Jason, tyrant of Pheræ, was elected power of ob- Tagus (chief-magistrate) of all Thessaly. The rule of cessors became so unbearable that aid was sought from Philip of Macedon, who in 344 subjected the country to Macedonia. Thessaly remained subject to the Macedonian kings till the victory of Cynoscephalæ, in 197 b. c., brought it under the protection of Rome. Under the emperors Thessaly was united with Macedonia, but after Constantine it was a separate province. In A. D. 1204 with other portions of the Eastern Empire, it came under the dominion of the Venetians, and in 1355 was taken by the Turks. The restoration to Greece of Thessaly S. of the Salambria was recommended by the Berlin Congress in 1878; and subsequently various modifications of the Greco-Turkish frontiers were proposed, the Greeks endeavoring to secure the cession of the whole of Thessaly. War between Greece and Turkey seemed imminent; but in 1881 Turkey agreed to cede, and Greece to accept, Thessaly S. of the ridge of mountains forming the watershed of the Salambria (the ancient Peneus), by much the largest and most fertile section of the province. The Greek portion constitutes the three monarchies of Larissa, Trikhala, and Phthiotis with Phocis.
Aiton's Encyclopedia (1910)
thes'a-li, in ancient history, a region lying between northern Greece and Macedonia. It is surrounded by mountains. It consists practically of a single river basin about sixty miles in diameter which discharges its waters through the famous Vale of Tempe between Mounts Olympus and Ossa into the Aegean Sea. The land was fertile and, for Greece, comparatively level. The inhabitants were of mixed Greek and Macedonian descent. They were famous for a race of horses. They furnished Greeks, Macedonians, and Persians with contingents of cavalry. Thessaly lay in the route of Xerxes' invading army. The final engagement between the troops of Pompey and Julius Caesar was fought out on the plain of Pharsalia, August 9, 48 B. C. The district was held long by the Turks. It is now a part of the modern kingdom of Greece. See Macedonia