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 is known to have dominated Anglo-Saxon's?, Context: The Vikings established Danelaw over much of the eastern and northern part of England with its boundary roughly stretching from London to Chester. It was an area of political and geographical control imposed by the Viking incursions which was formally agreed to by the Danish warlord, Guthrum and west-Saxon king, Alfred the Great in 886 AD. The Anglo-Saxon Chronicle recorded that London was "refounded" by Alfred the Great in 886. Archaeological research shows that this involved abandonment of Lundenwic and a revival of life and trade within the old Roman walls. London then grew slowly until about 950, after which activity increased dramatically.
Solution:
Danelaw