You will be given a definition of a task first, then some input of the task.
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.

Passage: Hakon Sverresson appeared to have pacified the whole country, but died suddenly in 1204. His successor was the infant Guttorm, who himself died later the same year. The Birkebeiner knew of no other direct descendants of King Sverre and chose one of his nephews, Inge Bardson, as their new king. By then a revived Bagler party had formed in Denmark, taking another son of King Magnus Erlingsson, Erling Stonewall, as their king. Helped by King Valdemar II of Denmark, they launched an invasion of Norway in 1204, taking control of the Oslofjord-area. This second Bagler war lasted until 1208. When Erling Stonewall fell ill and died in 1207, he was succeeded as Bagler king by Philippus Simonsson, a nephew of King Inge Crouchback and bishop Nikolas of Oslo, and the war continued uninterrupted. The Bagler were strongest in the Oslofjord-area, while Trndelag was a stronghold of the Birkebeiner, but battles and ambushes took place throughout the country. In the end the bishops were able to negotiate a settlement between the two sides, confirmed at a meeting at Kvitsy in 1208. The Bagler king Philippus was to remain in control of eastern Norway but renounce the title of king, leaving the Birkebeiner King Inge nominally sole ruler of the country. In the event, Philippus continued to style himself king until his death, but peace between the Bagler and Birkebeiner was preserved until 1217.
Question: How many years did peace last after the meeting at Kvitsy?
Answer type: Number
Output:
9.