Austro-Hungarian foreign minister whose ultimatum to Serbia (July 23, 1914) was followed (Aug. 1) by the outbreak of World War I.

A wealthy landowner in Hungary and Moravia, Berchtold, through marriage, became one of the richest men in Austria-Hungary. He entered the diplomatic service in 1893, held posts in Paris and London, and in 1906 was appointed ambassador to Russia. On Feb. 19, 1912, after the death of Aloys, Count Lexa von Aehrenthal, Berchtold reluctantly succeeded him as foreign minister. He soon fell under the influence of Franz, Count Conrad von Hötzendorf, chief of the general staff, but was restrained by the heir presumptive, Archduke Francis Ferdinand. At the beginning of the First Balkan War (October–December 1912), Berchtold unrealistically attempted to maintain the territorial status quo, and after the war he prevented Serbia from gaining a corridor to the Adriatic Sea. He was subsequently confronted with the Serbian ambition to form a state comprising all the South Slav peoples, including those subject at that time to Austria-Hungary. His vacillation aggravated the tension between Austria and Serbia, leading to the assassination of Archduke Francis Ferdinand by a Bosnian Serb at Sarajevo, Bosnia, June 28, 1914.

Encouraged by Conrad von Hötzendorf, who for years had urged a preventive war against Serbia, Berchtold, with the consent of the council of joint ministers, decided on an ultimatum, the onerous terms of which would assure its rejection by the Serbian government. He informed Germany, which granted Austria-Hungary a “blank check” for unconditional support, but not Italy, for fear that Rome would report immediately to St. Petersburg and thereby hasten the mobilization of Russia on Serbia's side—a prospect that Berchtold earlier had failed to take seriously. After the outbreak of the war, when Italy demanded territory from Austria-Hungary in return for no more than “benevolent neutrality,” Berchtold was forced to resign Jan. 13, 1915. He then accepted high office at court.