When the Apostle Paul travelled through Europe preaching the gospel he took advantage of the great system of roadways which had been built by the Romans. After landing in Europe at Neapolis, he followed the Via Egnatia through Philippi, Amphipolis, Apollonia, and Thessalonica.
While in Thessalonica Paul preached at the "synagogue of the Jews" (Acts 17:4). There is not much left of ancient Thessalonica from the New Testament age.
One of the more important monuments from the Roman age is the majestic Arch of Galerius, which is located on the Via Egnatia. Early in the fourth century A.D. the Roman tetrarch Galerius transferred the capital of the province to Thessalonica and erected a series of monuments, mainly for personal use. This arch contains relief scenes extolling the victories of Galerius over the Persians in A.D. 297. Two of the four original pillars of the monument remain.