How did Britain and France get involved with ww1?

Answer 1

France got involved because France and Russia had a treaty of alliance. Serbia was an independent country, and the Serbian intelligence service backed an organization of Serbian nationalists called The Black Hand. The Black Hand assassinated the heir to the throne of the Austro-Hungarian Empire, and his wife. The Austrians were furious and made very harsh demands of Serbia. Russia had no treaty with Serbia but historically the Russians had considered Russia to be the "mother of the Slavs". So though not obligated to do so, the Russians decided to intervene and take Serbia's part. Had the Russians not intervened, it would have remained a dispute between Serbia and the Austro-Hungarian Empire. Since Russia meddled, and Russia was the largest European nation, with the biggest army, the Hapsburg rulers of the Austro-Hungarian Empire called on their ally, the Germans, for assistance. The alliance between France and Russia was aimed at Germany. Since the Franco-Russian alliance Germany knew that war with either France or Russia meant war with both. The German army had planned for what to do if Germany got into such a two-front war. They developed a plan which called for beating France quickly, before Russia could get fully mobilized. After France was defeated, Germany could turn its entire attention to Russia. So with war now imminent with Russia, the Germans attacked France.

As part of the plan to beat France quickly, the Germans had decided to invade France by going through neutral Belgium. This would allow the Germans to go around the French border defenses. But Germany and three other great powers were bound by an 1837 Treaty to perpetually respect and defend Belgian neutrality. Nevertheless, in 1914 the Germans invaded Belgium, on the way to France, because they were about to go to war with Russia. Great Britain was another party to the 1837 treaty guaranteeing Belgian neutrality. When German troops crossed the border into Belgium the British demanded that the Germans stop the invasion and withdraw from Belgium. The German foreign minister scornfully denounced the 1837 treaty as "a scrap of paper". So Britain went to war over the German violation of Belgian neutrality, as obligated to do so under the treaty.