Detailed Instructions: This task involves creating answers to complex questions, from a given passage. Answering these questions, typically involve understanding multiple sentences. Make sure that your answer has the same type as the "answer type" mentioned in input. The provided "answer type" can be of any of the following types: "span", "date", "number". A "span" answer is a continuous phrase taken directly from the passage or question. You can directly copy-paste the text from the passage or the question for span type answers. If you find multiple spans, please add them all as a comma separated list. Please restrict each span to five words. A "number" type answer can include a digit specifying an actual value. For "date" type answers, use DD MM YYYY format e.g. 11 Jan 1992. If full date is not available in the passage you can write partial date such as 1992 or Jan 1992. If you find multiple spans, please add them all as a comma separated list. Please restrict each span to five words.
Problem:Passage: Between 1519 and 1523 there was a succession of heavy battles and smaller skirmishes, in the course of which many towns and villages were devastated. After futile sieges of the defences of Calenberg and Hildesheim by troops from Hildesheim or Brunswick as well as numerous trails of devastation and plundering by both sides against the civilian population, the two sides finally met on 28 June 1519 at the Battle of Soltau . The Hildesheim army scored an emphatic victory against the Brunswick-Welf troops, killing some 3,500 men and capturing one of their leaders, Eric of Calenberg, as well as many of the nobles. This signalled the end of the opening phase of the war. However, an appeal to the newly elected emperor, Charles V, who had a good relationship with Wolfenbuttel, saw the situation entirely reversed at a political level. The ruling imposed by Charles V provided for the surrender of all conquered territory and release of all the prisoners, and thus ruled very much against the Hildesheim side. Because it was ignored by the bishop and his allies, the emperor's decision was followed in 1522 by the imposition of an imperial ban, the execution of which was assigned to the princes of Wolfenbuttel and Calenberg. Whilst Henry of Luneburg had already gone into exile in France in 1520 having transferred the reins of power to his sons and in doing so keeping the Principality of Luneburg out of the subsequent conflict, there were renewed military clashes between the Hildesheim prince-bishop and his opponents that were not finally resolved until the so-called 'field peace' of 15 October 1521. Hildesheim had won militarily, but lost politically.
Question: How many years after the Battle of Soltau was the emperor's decision followed by the imposition of an imperial ban?
Answer type: Number
Solution:
3.