You will be given a definition of a task first, then an example. Follow the example to solve a new instance of the task.
In this task, you are given a question and a context passage. You have to answer the question based on the given passage.

what is the first event mentioned?, Context: The Russian Revolution is the series of revolutions in Russia in 1917, which destroyed the Tsarist autocracy and led to the creation of the Soviet Union. Following the abdication of Nicholas II of Russia, the Russian Provisional Government was established. In October 1917, a red faction revolution occurred in which the Red Guard, armed groups of workers and deserting soldiers directed by the Bolshevik Party, seized control of Saint Petersburg (then known as Petrograd) and began an immediate armed takeover of cities and villages throughout the former Russian Empire.
Solution: Russian Revolution
Why? This is a good example, and the Russian Revolution is the first event mentioned.

New input: What happened during Pax Britannica?, Context: When Russia invaded the Turkish Balkans in 1853, fears of Russian dominance in the Mediterranean and Middle East led Britain and France to invade the Crimean Peninsula to destroy Russian naval capabilities. The ensuing Crimean War (1854–56), which involved new techniques of modern warfare, and was the only global war fought between Britain and another imperial power during the Pax Britannica, was a resounding defeat for Russia. The situation remained unresolved in Central Asia for two more decades, with Britain annexing Baluchistan in 1876 and Russia annexing Kirghizia, Kazakhstan, and Turkmenistan. For a while it appeared that another war would be inevitable, but the two countries reached an agreement on their respective spheres of influence in the region in 1878 and on all outstanding matters in 1907 with the signing of the Anglo-Russian Entente. The destruction of the Russian Navy by the Japanese at the Battle of Port Arthur during the Russo-Japanese War of 1904–05 also limited its threat to the British.
Solution:
Crimean War