As a historian with a focus on the early 20th century, I specialize in the intricate web of alliances and the complex series of events that led to the outbreak of the First World War. It's a period of history that is often misunderstood, with many assuming that a single declaration of war was the spark that ignited the conflict. In reality, the situation was far more nuanced, with a cascade of diplomatic and military actions that drew the major powers of the time into a global conflict.
The First World War, also known as the Great War, began in the aftermath of the assassination of Archduke Franz Ferdinand of Austria on June 28, 1914. This event set off a chain reaction of ultimatums, mobilizations, and declarations of war among the various European powers. It's important to note that the war was not a simple case of one country declaring war on another, but rather a series of interconnected events that unfolded over several weeks.

On July 28, 1914, the first declaration of war occurred when Austria-Hungary declared war on Serbia. This was a direct response to the assassination of Archduke Franz Ferdinand, which Austria-Hungary believed was orchestrated by Serbian nationalists. The ultimatum that Austria-Hungary sent to Serbia was intentionally severe, making it nearly impossible for Serbia to comply fully, which was Austria-Hungary's intention.

On August 1, 1914, as you mentioned, Germany declared war on Russia. This occurred because Russia had begun a period of military mobilization in support of Serbia, which Germany, an ally of Austria-Hungary, viewed as a threat. Germany had a commitment to support Austria-Hungary through a series of alliances and treaties, most notably the Dual Alliance of 1879 and later the Triple Alliance that included Italy and was formalized in 1882.

Also on August 1, 1914, France ordered a general mobilization, although it did not immediately declare war. France was allied with Russia through the Franco-Russian Alliance of 1894, and the mobilization was a response to the German declaration of war on Russia. France was obligated to support its ally, and the mobilization was a precursor to entering the war.

On August 3, 1914, Germany declared war on France. This was due to France's support for Russia and the German Schlieffen Plan, which was a strategic military maneuver designed to avoid a two-front war by quickly defeating France before turning to the east to confront Russia.

On August 4, 1914, the United Kingdom declared war on Germany. This was triggered by Germany's violation of Belgian neutrality as it attempted to execute the Schlieffen Plan. The UK had signed the 1839 Treaty of London, which guaranteed Belgian neutrality, and thus felt compelled to intervene.

The war quickly escalated from these initial declarations, drawing in countries from around the world. The Triple Entente, consisting of Russia, France, and the United Kingdom, and the Triple Alliance, consisting of Germany, Austria-Hungary, and Italy (which later switched sides), were the two main opposing alliances in the conflict.

In conclusion, the First World War was not started by a single declaration of war but was the result of a complex interplay of alliances, treaties, and strategic considerations. The initial declarations of war by Austria-Hungary against Serbia, Germany against Russia, and Germany against France, along with the mobilization orders by Russia and France, set the stage for a conflict that would engulf the globe.

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On August 1, 1914, four days after Austria-Hungary declared war on Serbia, two more great European powers--Russia and Germany--declare war on each other; the same day, France orders a general mobilization.read more >>