The evolution of city growth is usually studied for relatively short time periods. The rise and decline of cities is, however, typically a process that takes many decades or even centuries. In this article we study the evolution of Italian cities over the period 1300–1861. Using an existing data set, we perform panel estimations where the development of city size and urban patterns can be explained by various geographical, institutional and other determinants of city size for the period under consideration. Although large shocks such as the plague epidemics are clearly visible in the data, our baseline estimation results show that the main determinants of Italian city growth are physical geography and the predominance of capital cities. With respect to geography, being a seaport or having access to navigable waterways increases city size whereas a city's relative location, measured by its urban potential, is not significant. Being a capital city also increases city size. The estimation results reveal strong century-specific effects on city growth and these effects differ markedly between the North and South of Italy. Additional estimations show that these time effects can be linked to the political and institutional developmental changes over time in Italy. Our findings that the capital city bonus increases and non-capital cities suffer when the political power and the institutions of the state are more centralised corroborate the idea that institutions are a key factor in explaining Italian city growth.