In preparation for the peace conference that was expected to follow World War I, in the spring of 1917 the British Foreign Office established a special section responsible for preparing background information for use by British delegates to the conference. Transylvania and the Banat is Number 6 in a series of more than 160 studies produced by the section, most of which were published after the conclusion of the 1919 Paris Peace Conference. Transylvania consisted of 15 counties in the southeastern part of the Kingdom of Hungary, which in turn was part of the Austro-Hungarian Empire. The Banat was made up of three counties in Hungary to the southwest of Transylvania. Both regions had highly heterogeneous populations. According to the 1910 census, the population of Transylvania (2,678,367) was 55 percent ethnically Romanian, 34 percent Hungarian, 9 percent German, with the remainder mainly Slovak, Ruthenian, Croat, and Serb. The population of the Banat (2,141,769) was 39 percent Romanian, 22 percent Hungarian, 20 percent German, and 14 percent Serb. The study notes that “political questions in Transylvania are mainly racial” (i.e., ethnic), and makes the same point with regard to the Banat. The book includes sections for each region on physical and political geography, political history, social and political conditions, and economic conditions. With the defeat of the Central Powers in World War I and subsequent breakup of the Austro-Hungarian Empire, Transylvania became part of an enlarged Romania, while most of the Banat was divided between Romania and the newly established Kingdom of Serbs, Croats, and Slovenes (Yugoslavia from 1929).