After the final expulsion of the Turks in 1699 it became possible to carry out detailed surveys of the territory of Hungary. Drawing on data garnered by an Italian military engineer, Luigi Ferdinano Marsigli, in the service of the Austrian Emperor, Johann Christoph Müller drew this map, the first of Hungary to be based on actual measurements. Müller carried out measurements along the banks of the rivers Danube and Tisza to establish the country’s geographical latitude. These were the first astronomical observations to be carried out in Hungary expressly for higher (surface) geodetic purposes. The most striking change on this map as compared with previous ones is that the course of the Danube is shown accurately. To depict Transylvania Müller used Giovanni Morando Visconti’s Mappa della Transiluania [...], published in Nagyszeben (Sibiu, Romania) in 1699. Of the 2,500-copy run, the Hungarian Treasury planned to distribute 500 among officials and the higher nobility. This map had its own register of place-names, listing more than 4000 settlements.