Teacher: In this task, you are given a question and a context passage. You have to answer the question based on the given passage.
Teacher: Now, understand the problem? If you are still confused, see the following example:
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
Reason: This is a good example, and the Russian Revolution is the first event mentioned.

Now, solve this instance: when did the the city become strategically important, Context: A few centuries later, coinciding with the first waves of the invading Germanic peoples (Suevi, Vandals and Alans, and later the Visigoths) and the power vacuum left by the demise of the Roman imperial administration, the church assumed the reins of power in the city and replaced the old Roman temples with religious buildings. With the Byzantine invasion of the southwestern Iberian peninsula in 554 the city acquired strategic importance. After the expulsion of the Byzantines in 625, Visigothic military contingents were posted there and the ancient Roman amphitheatre was fortified. Little is known of its history for nearly a hundred years; although this period is only scarcely documented by archeology, excavations suggest that there was little development of the city. During Visigothic times Valencia was an episcopal See of the Catholic Church, albeit a suffragan diocese subordinate to the archdiocese of Toledo, comprising the ancient Roman province of Carthaginensis in Hispania.
Student:
554