CASTLES

The defining characteristic of the modern state is its monopoly on violence. Yet, despite broad scholarly agreement on the definition, there are no empirical measures of the monopolization of violence. We introduce the first such measure: the share of castles controlled by the Crown. Taking the canonical definition as its point of departure, the measure allows us to trace the origins of the modern state in the power struggle between monarchs and societal actors when, where, and as it actually happened. The Castles Data are based on random samples from 17 modern European countries and record the ownership of more than 5,400 unique castles across most of Europe from 1000 to 1700. To validate the measure, we show that it tracks historiographical accounts of state formation and correlates strongly with independent coding by historians. We illustrate its use in applications at both the polity and micro levels.

For more details, see Cappelen & Hariri (2026). The State and the Monopolization of Violence: Castles in Europe, 1000–1700. Comparative Political Studies

Data

The Castles data consist of 3 separate data sets:

• Castles data: Castle-by-year data with information on location and ownership
• Polity data: Polity-by-year data with aggregated information on castle ownership within a historical polity
• Registry data: Geo-coded collection of castles from national registries from which the primary data set was sampled.

Download the complete data here: Download

Download individual files:

• Castles data
• Polity data
• Registry data
• Codebook