Q: In this task, you're given a passage, further information available on a particular linked term from the statement, and a question. Your job is to generate the answer to the question by using the information provided. If there is no clear answer obtainable, output 'none'.
Passage: This town was strategically located at a junction of trade routes between the Mediterranean Sea and the North Sea regions, and the Rhine and Danube rivers. In 1200, Freiburg's population numbered approximately 6,000 people. At about that time, under the rule of Bertold V, the last duke of Zahringen, the city began construction of its Freiburg Munster cathedral on the site of an older parish church. Begun in the Romanesque style, it was continued and completed 1513 for the most part as a Gothic edifice. In 1218, when Bertold V died, then Egino V von Urach, the count of Urach assumed the title of Freiburg's count as Egino I von Freiburg. The city council did not trust the new nobles and wrote down its established rights in a document. At the end of the thirteenth century there was a feud between the citizens of Freiburg and their lord, Count Egino II of Freiburg. Egino II raised taxes and sought to limit the citizens' freedom, after which the Freiburgers used catapults to destroy the count's castle atop the Schloberg, a hill that overlooks the city center. The furious count called on his brother-in-law the Bishop of Strasbourg, Konradius von Lichtenberg, for help. The bishop responded by marching with his army to Freiburg.
Link Information: Berthold V (1160 Question: How old was Bertold V when the construction of Freiburger Munster began?
A:
Answer: 40