One hundred years ago in October 1914, it might be said that the ‘spirit of 1914’ had already disappeared across Austria-Hungary. This was true among civilians in Ljubljana or Prague, or even in Vienna or Budapest where people had first been most enthusiastic about the war. But it was true too for many soldiers at the front, where the initial excitement about victory was quickly disappointed. The Habsburg armies did not quickly crush little Serbia; nor did they manage a quick victory over Russia. Instead, the troops were retreating right back into Galicia, while in the Balkans it was Serbia’s army that was penetrating into Bosnia. This suggests to us immediately that the ‘spirit of 1914’ – the enthusiasm that accompanied the outbreak of war – lasted only a few months. However, this time period as measured in days and weeks was also relative because of what was actually experienced. Many civilians and soldiers felt in the summer of 1914 that they had lived a whole lifetime. One officer wrote later that by late August he had drawn a line under his former life, for he was now entering a different world where events were constantly speeding up. The war, which started in an enthusiastic ‘spirit’, began within two months to transform itself from life into death. Indeed, the spirit of 1914 disappeared as the phenomenon of mass death began to appear in towns and villages across the monarchy. This lecture explores what we can learn from this short episode, this ‘spirit of 1914.’ It explores the different mindsets of those who entered the war, but also the different loyalties that existed in the late Habsburg monarchy: a complex mixture of imperial, national and regional. If the war became an experiment in a true multinational (Habsburg) mission, the ‘spirit of 1914’ was the start of that mission and the authorities tried to capture and prolong it for as long as possible. What was this ‘spirit’, and how can historians measure it? Who was directing it and how long did it really last? The answers can tell us much about why the Habsburg monarchy failed in its final mission and why it disintegrated in 1918.