ORBIS is a web-based tool that makes it possible for the first time to simulate the time cost and financial expense incurred by travel and transportation around the Roman Empire. In this workshop, you will learn to use ORBIS to (e.g.) find the fastest route between Londinium and Constantinopolis, calculate the cost of shipping wheat from Alexandria to Rome, and make your own distance cartogram to represent travel times from Antioch to more than 600 other locations throughout the Roman Empire. In the premodern world, cost—in terms of time and money—rather than distance was the primary determinant of connectivity. Conventional maps that depict the world as it appears from space thus misrepresent the constraints that governed flows of people, goods, and information around the ancient Mediterranean. By simulating movement along the principal routes of the Roman road network, the main navigable rivers, and hundreds of sea routes in the Mediterranean, Black Sea, and coastal Atlantic, ORBIS allows its users to calculate the duration and financial cost of travel throughout the Roman Empire and to generate a variety of visualizations on the basis of those calculations. In so doing, it reveals the true shape of the Roman world and provides a unique resource for our understanding of both Roman and pre-modern history more generally.