This paper explores whether modern economic theory could have been applied during the classical Greco-Roman era. The main theory behind this paper is that of the International Trade Model. From this model, I investigate other models such as the Hecksher-Olin Trade Theory, the Gravity Model, and the Ricardian Model. The main goal of this paper is to determine if the Romans had such an advanced economy that modern economic theory would have be feasible over 1500 years ago. Using modern classicists' work and compiling my own data I attempt to draw conclusions based on these economic theories. My main contribution to the existing literature in this field is through my collection and analysis of data from the ORBIS Geospatial Network Model of the Roman World (developed at Stanford University). This database allows me to see the relationship between the distance of ancient trade routes between cities as it relates to those cities' population today. The main goal is to determine if there is a correlation between the distance travelled between a specific city in antiquity to an economic center (Rome, Alexandria, Athens) and the population of modern cities. Previous work has focused specifically on distance between cities as it related to the price of goods. I am interested to see if distance in ancient trade had lasting effects of about 1800 years. In economics, the gravity model states that the distance between two places can often determine the level of interaction between them. Therefore, using ORBIS, I determine the distance between two cities using trade routes rather than just linear distance. I made 48 observations of cities using ORBIS and each of the 51 has an average distance from each center. I find that there is some evidence that supports population decreases as the distance from the economic center decreases. There are some outliers and this paper attempts to explain this phenomenon. On top of this conclusion, I find that there is some evidence that supports modern economic theory does hold up in antiquity, but loosely. Due to the nature or availability of classical data, to say that the Heckscher-Olin model could have existed in Antiquity would be false. However, certain aspects of each of the mentioned modern economic theories pertained in Antiquity.