Christianity was an urban religion, flourishing in the towns and cities. Only its Marcionite variant
really captured the rural population. The Roman empire was remarkably urbanised. During the high Middle
Ages, call it 1300, only one in twenty Europeans resided in towns and cities. Modern studies believe
that one in four people in the Roman empire lived in towns and cites. The United States did not achieve
Roman levels of urbanisation until the late 19th century.
A cartogram is a thematic map in which geography is distorted to show some other variable. This cartogram
distorts each area in the Roman empire so that its size is proportional to its urban population. Areas in red are majority Latin speaking, and those in dark blue are majority Greek speaking.