Fig. 1

Visualization of available data and division of cities into regions. a Map of Roman roads and cities with Roman status in Northern Tunisia at 350 AD. City statuses marked with * denote cities with at least this status. (Map was made by Fleur Schweigart) b Geographical position of Roman cities and their division into four regions. Color of a city indicates a region it belongs to. c Observed number of romanized cities in the period 0–350 AD for each region corresponding to the division from Fig. (b).