In 1867, after facing several political and military difficulties, including a significant defeat in a war against Prussia (a powerful north German state that eventually unified Germany), the Austrian Empire had to rethink its structure. To address the demands of the Magyar - Hungarian - population for more autonomy and to stabilize the empire, a compromise was reached. This compromise is known as the "Ausgleich" (German for "Compromise") of 1867, which created the Dual Monarchy of Austria-Hungary.
This compromise was a problem because, in the late 19th century, it was clear the Austrian Empire required reform, but it was stopped by the Habsburgs' desire to maintain their rule in Hungary and the Hungarian elites’ desire to be an independent power. Separatists in Hungary waged a political campaign against those who supported the compromise. In practice, this meant the Magyars, the people also known in English as Hungarians, continually wrung concessions out of the monarchy while sabotaging attempts to make the empire more efficient, inclusive, and functional. While normally, Hungarian desire for self-determination and nationalism might be respectable and unremarkable for 18th-20th century European history; the Magyar separatists wanted something that was impossible given their actual power: to be sovereign while denying sovereignty to others. To use the vernacular, they didn’t have a stroke.
