historical events commonly rely on population as a proxy for prosperity.<sup>29</sup> Third, as argued by Bairoch (1988), population density is closely related to urbanization, and it has been used as a proxy of urbanization in many studies of history (e.g., Acemoglu et al. 2002; Chen and Kung 2016; Jia 2014).<sup>30</sup> Finally, by Malthus’s argument, only areas with high productivity can afford a high population density (Malthus 1798). We recognize that after the Malthusian regime (Galor and Weil 2000), a better measure of development is income per capita, and that slower population growth, in fact, could be a key sign of high-quality development.

We use two data sets for population. One is from the commonly used Cao (2001), covering 266 of all 317 prefectures in China (Chen and Kung 2016; Jia 2014). It records population once about every three decades between 1820 and 1953. The other source is the national censuses for 1953, 1982, and 2000. Using the historical GIS maps of China, we merge the contemporary census data set with the historical population data sets, after considering different administrative boundary changes.<sup>31</sup> In the end, we rely on seven snapshots across two centuries (i.e., years 1820, 1851, 1880, 1910, 1953, 1982, and 2000) for population evolution.

To see the long-term development impact, we also consider modern outcomes. Income is captured by GDP per capita in 2010.<sup>32</sup> Fiscal capacity is measured by fiscal revenue per capita in 2010,<sup>33</sup> industrialization by the shares of manufacturing and of non-agricultural employment in 2000, and human capital by the average years of schooling and the mortality rate.

_The Taiping Rebellion_ **.** Based on Guo (1989) and Hua (1991) (see Appendix B), we construct two Taiping treatments. The first concerns all the areas in the Taiping jurisdiction (“Taiping”). The second concerns all those that were occupied by the Taiping Army but not officially under Taiping control (“Occupied”).<sup>34</sup> We use the Qing boundary in 1820 to define Early and Late and require Early and Late prefectures to be under Taiping control during that Stauffer (1922). Ullman (1961) offers a more comprehensive population estimation of cities in China in 1938, 1953, and 1957. Perkins (1969) tallies the population of cities in China in 1910 and 1920. Historical measures of urbanization have serious measurement issues. For example, in the Yangzi River area, where clustered market towns were close to each other, the distinction between rural and urban areas is blurred (Brandt et al. 2014). 29 See Acemoglu (2002), Davis and Weinstein (2002), Brakman et al. (2004), Jia (2014), Chen and Kung (2016). 30 However, no similar cross-sectional relationship can be found using recent data, likely because the demographic relationship between income and the number of children has changed (Livi Bacci, 1992).

> 31 Using the administrative boundary in 1820 as the benchmark for the prefectures, we calculated the population in the same prefecture for different periods from 1953 to 2000 using the area as the weight, assuming that the population distributes evenly inside the prefecture.

> 32 Because the data come from various sources, the modern variables center around years 2000 to 2010, but are not of the same year. See Appendix B for data sources.

> 33 For most variables, the jurisdiction is based on the Qing Dynasty.

> 34 - In defining Taiping prefectures, our main source of data is " 太平天国地理志 华强 " (Taiping Kingdom MapsHuang Qiang).  To implement, we first coded Taiping-influenced area at the county level using the Qing 1893 administration boundaries, then converted it in to Qing 1820 administration boundaries (between 1820 and 1893). In our research we thus use the administration boundary of prefectures and provinces in the year 1820.

23