After the partition of the Empire in 395, the Peloponnese became a part of the East Roman or Byzantine Empire. The devastation of Alaric's raid in 396–397 led to the construction of the Hexamilion wall across the Isthmus of Corinth. Through most of late antiquity, the peninsula retained its urbanized character: in the 6th century, Hierocles counted 26 cities in his Synecdemus. By the latter part of that century, however, building activity seems to have stopped virtually everywhere except Constantinople, Thessalonica, Corinth, and Athens. This has traditionally been attributed to calamities such as plague, earthquakes and Slavic invasions. However, more recent analysis suggests that urban decline was closely linked with the collapse of long-distance and regional commercial networks that underpinned and supported late antique urbanism in Greece, as well as with the generalized withdrawal of imperial troops and administration from the Balkans. Slavic invasion, settlement and decline The scale of the Slavic invasion and settlement in the 7th and 8th centuries remains a matter of dispute, although it is nowadays considered much smaller than previously thought. The Slavs did occupy most of the peninsula, as evidenced by the abundance of Slavic toponyms, but these toponyms accumulated over centuries rather than as a result of an initial "flood" of Slavic invasions, and many appeared to have been mediated by speakers of Greek, or in mixed Slavic-Greek compounds. Fewer Slavic toponyms appear on the eastern coast, which remained in Byzantine hands and was included in the thema of Hellas, established by Justinian II c. 690. While traditional historiography has dated the arrival of Slavs to southern Greece to the late 6th century, according to Florin Curta there is no evidence for a Slavic presence in the Peloponnese until after c. 700 AD, when Slavs may have been allowed to settle in specific areas that had been depopulated. Relations between the Slavs and Greeks were probably peaceful apart from intermittent uprisings. There was also a continuity of the Peloponnesian Greek population. This is especially true in Mani and Tsakonia, where Slavic incursions were minimal, or non-existent. Being agriculturalists, the Slavs probably traded with the Greeks, who remained in the towns, while Greek villages continued to exist in the interior, governing themselves, possibly paying tribute to the Slavs. The first attempt by the Byzantine imperial government to re-assert its control over the independent Slavic tribes of the Peloponnese occurred in 783, with the logothete