Unequal distribution of wealth is a matter of growing concern in contemporary society, but it is also one with deep roots in the past. Several authors have traced the origins of this inequality by reconstructing historical series and collecting and harmonising data from sources and records with uneven territorial and temporal cover (Milanovic et al. (2011), Alfani (2015) Piketty (2014 and 2020)). Few places in the world have data series that make it possible to reconstruct the patterns of socioeconomic inequality by drawing on a single source. Barcelona, including its hinterland, is one of these places. The Barcelona Historical Marriage Database, which was created under the auspices of the Advanced Grant project Five Centuries of Marriages headed by Professor Anna Cabré, has made it possible to analyse, over a period of fve centuries, the distribution of wealth by studying the taxes levied on marriages held in the Diocese from 1451 to 1880. This number of Perspectives Demogràfques offers an account of the evolution of inequality from the ancien régime through to the consolidation of industrialisation, the concentration of wealth, and the composition and replacement of economic elites in the Barcelona area. Five Centuries of Inequality and Socioeconomic Transformation in the Barcelona Area, 1451 – 1880 Joana Maria Pujadas-Mora, Centre d’Estudis Demogràfcs, Universitat Autònoma de Barcelona; Gabriel Brea- Martínez, Department of Economic History, Lund University (Sweden) MEASURING INEQUALITY WITH THE BARCELONA HISTORICAL MARRIAGE DATABASE The Barcelona Historical Marriage Database (BHMD) brings together the tax and occupational data provided by the Llibres d’Esposalles (Marriage license books) of the Diocese of Barcelona, which cover the years from 1451 to 1905. These books record the taxes levied on marriages held in the Diocese of Barcelona with the aim of fnancing the construction and subsequent maintenance of the city’s cathedral. Accordingly, the BHMD contains tax information pertaining to more than 600,000 marriages occurring between the ffteenth and twentieth centuries and covering approximately 250 parishes distributed in the present-day Baix Llobregat, Barcelonès, Maresme and Vallès Occidental regions, which include big cities like Barcelona, Mataró, Sabadell and Terrassa. Recorded with each marriage are the given names and surnames of the bride and groom, place of residence or parish of the ceremony, groom’s occupation, and amount of the marriage tax or fee paid, though this is information that can vary over time. A tax was paid for each marriage, varying in accordance with the socioeconomic status of the bride and groom. This was classifed into large groups: 1) Nobility, 2) Military, 3) Honoured citizens (those holding public offce), 4) Merchants, doctors of law or medicine, 5) Guild masters, 6) Peasants and Artisans, and 7) Those classifed as poor. Even if the poor declared an occupation, they were exempt from FIGURE 1. Gini coeffcient for the Barcelona area, 1481-1880 Note: In order to calculate the Gini coeffcient on the basis of the concept of “ability-to-pay”, it has been necessary to transform occupations/social status into a continuous numerical value and, for this purpose, the international scale for classifying social/occupational stratifcation HISCAM has been used (Lambert et al., 2013).. Source: BHMD and Brea-Martínez, Gabriel; Pujadas-Mora, Joana Maria (2019) “Estimating Long-Term Socioeconomic Inequality in Southern Europe: The Barcelona Area, 1481–1880”. European Review of Economic History, 23(4): 397-420. Centre d’Estudis Demogràfcs PERSPECTIVES DEMOGRÀFIQUES Num. 018 JAN 2020 Perspectives Demogràfques / https://doi.org/10.46710/ced.pd.eng.18 Num. 018 JAN 2020 01 04