Macedonia's strategic importance at the crossroads of the major arterial roads in the Balkan peninsula meant that during the critical period marking the transition from the late Roman to the Byzantine period it was the object of benefactions from the royal house, despite the general upheavals of the times. Manifestations of this interest included the transfer of the capital to Thessalonica by Galerius Maximian, and the erection there of an imposing palace; the construction in the same city of a capacious dock yard by Constantine the Great (AD 322/323), and the choice of the capital of Macedonia as the headquarters of Theodosius the Great (AD 379/380) for his campaigns against the Visigoths and Ostrogoths. The economic prosperity of Macedonia in the 4th and 5th centuries AD is at tested by the large numbers of quarries (Thasos, Prilep), furnaces for the smelting of metals, work shops for the construction of weapons and metal objects, pottery workshops and centers producing beads of glass-paste; there is also evidence for the existence of extensive farms, salt-flats, yarn dyers (Stoboi), the organizing of trade fairs ("Demetria") and the carrying on of a trade in leather. This prosperity was undoubtedly responsible for the imposing buildings (whether of a religious or secular character) brought to light in many places by the archaeologist's spade: basilicas, villas and fortifications.