August Sedláček in the Age of Digital Humanities

August Sedláček (1843–1926) is one of a few Czech historians whose name is known outside the narrow circle of the historical community. His most famous work, the fifteen-volume Hrady, zámky a tvrze království Českého [Castles, Chateaux and Strongholds of the Kingdom of Bohemia], is comprehensible to the lay public, but also its professional quality is so far undoubtable. For the preparation of his monumental work, August Sedláček created a number of auxiliary materials, which are preserved to this day in state archives and, above all, at the Institute of History of the Czech Academy of Sciences in Prague (https://www.hiu.cas.cz/pozustalost-augusta-sedlacka). All of these materials themselves have high scientific and historical value. In particular, two card indices (genealogical and topographical), comprising altogether about 400 000 cards, are to this day the most frequently used archival collections of the August Sedláček scholarly legacy. Since 2015, they are accessible to public as a digital database (http://www.augustsedlacek.cz). The special methodology and software developed for this purpose not only allow a standard access to each particular digitised index card, but make it possible to analyse the information contained in the card indices as a whole and provide their end users – the researchers – with comfortable room for their own interpretations.