While scholars have long documented the migration of people in ancient and medieval times, they have paid less attention to those who traveled across borders with some regularity. This study of early transnational relations explores the routine interaction of people across the boundaries of empires, tribal confederacies, kingdoms, and city-states, paying particular attention to the role of long-distance trade along the Silk Road and maritime trade routes. It examines the obstacles voyagers faced, including limited travel and communication capabilities, relatively poor geographical knowledge, and the dangers of a fragmented and shifting political landscape, and offers profiles of better-known transnational elites such as the Hellenic scholar Herodotus and the Venetian merchant Marco Polo, as well lesser known servants, merchants, and sailors. By revealing the important political, economic, and cultural role cross-border trade and travel played in ancient society, this work demonstrates that transnationalism is not unique to modern times.