This article presents an English translation and analysis of a new historical fragment, probably from Dexippus’ Scythica, published by Gunther Martin and Jana Grusková in 2014. The fragment, preserved in a palimpsest in the Austrian National Library, describes a Gothic attack on Thessalonica and the subsequent preparations of the Greeks to repel the barbarian force as it moved south into Achaia. The new text provides several important details of historical, prosopographical and historiographical significance, which challenge both our existing understanding of the events in Greece during the reign of Gallienus and the reading of the main literary sources for this period. In this article we look to secure the Dexippan authorship of the fragment, identify the individuals named in the text, and date the events described in the text to the early 260s a.d.