Thessalonica in the New Testament
Thessalonia was a town of Macedonia on the Thermaic gulf, now the gulf of Saloniki. Therma was its original name, which Cossander changed into Thessalonica in honour of his wife, Philip's daughter.
It rises from the end of the basin at the head of the gulf up the declivity behind, presenting a striking appearance from the sea. After the battle of Pydna Thessalonica fell under Rome and was made capital of the second region of Macedonia.
Afterward, when the four regions or governments were united in one province, Thessalonica became virtually the metropolis. Situated on the Via Ignatia which traversed the S. coast of Macedonia and Thrace, connecting thereby those regions with Rome, Thessalonica, with its harbour on the other hand connecting it commercially with Asia Minor, naturally took the leading place among the cities in that quarter.
Paul was on the Via Ignatia at Neapolis and Philippi, Amphipolis and Apollonia (Acts 16:11-40; 17:1), as well as at Thessalonica. The population of Saloniki is even now 60,000, of whom 10,000 are Jews. Trade in all ages attracted the latter to Thessalonica, and their synagogue here was the starting point of Paul's evangelizing.
Octavius Augustus rewarded its adhesion to his cause in the second civil war by making it "a free city" with a popular assembly ("the people") and "rulers of the city" (politarchs: Acts 17:1,5,8); this political term is to be read still on an arch spanning the main street, from it we learn there were seven politarchs. Its commercial intercourse with the inland plains of Macedonia on the N., and on the S. with Greece by sea, adapted it admirably as a center from whence the gospel word "sounded out not only in Macedonia and Achaia, but in every place" (1 Thes. 1:8).
Paul visited T. on his second missionary journey. Other Thessalonian Christians were Demas perhaps, Gaius (Acts 19:29), Secundus, and Aristarchus (Acts 20:4; 27:2; 19:29). On the same night that the Jewish assault on Jason's house in search of Paul and Silas his guests took place, the latter two set out for Berea. Again Paul visited Thessalonica (Acts 20:1-3), probably also after his first imprisonment at Rome (1 Tim. 1:3, in accordance with his hope, Phil. 1:25,26; 2:24).
Thessalonica was the mainstay of Eastern Christianity in the Gothic invasion in the third century. To Thessalonica the Sclaves and the Bulgarians owed their conversion; from whence it was called "the orthodox city." It was taken by the Saracens in 904 A.D., by the Crusaders in 1185 A.D., and by the Turks in 1430; and the murder of the foreign consuls in 1876 had much to do with the last war of 1876-1877, between Russia and Turkey.
Eustathius, the critic of the 12th century, belonged to Thessalonica. The main street still standing is the old Via Ignatia, running E. and W., as is shown by the two arches which span it, one at the E. the other at the W. end; on that at the E. end are figures in low relief representing the triumphs of a Roman emperor.
International Standard Bible Encyclopedia, which is in the public domain (with minor edits).