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: How did western samoa become a part of New Zealand?, Context: Under the terms of the concluding Treaty of Versailles signed in 1919, the empire reached its greatest extent with the addition of 1,800,000 square miles (4,700,000 km2) and 13 million new subjects. The colonies of Germany and the Ottoman Empire were distributed to the Allied powers as League of Nations mandates. Britain gained control of Palestine, Transjordan, Iraq, parts of Cameroon and Togo, and Tanganyika. The Dominions themselves also acquired mandates of their own: the Union of South Africa gained South-West Africa (modern-day Namibia), Australia gained German New Guinea, and New Zealand Western Samoa. Nauru was made a combined mandate of Britain and the two Pacific Dominions.
Solution:
Treaty of Versailles