Detailed Instructions: In this task, you're given a passage, further information available on a particular linked term from the statement, and an answer term. Your job is to generate a question that can use the information provided to obtain the given answer. You should use the information on both passage and link information to create the question. Note that the answer to the question should be exactly the given answer, and if the answer is none, the answer to the question shouldn't be obtainable from the passage or linked information.
Q: Passage: At the beginning of the 13th century, a Prussian trade route developed that crossed over an isthmus between two large lakes, the Sicieńskie lake and the Zamkowe ("Castle lake"). A defensive wall was built at this spot, and later, a settlement was constructed there as well. The place is mentioned in a twelfth-century document regarding a battle in which Henry of Sandomierz was killed. Under the name "Wambresia" the town was mentioned in a 1251 Prussian Document issued at Chełmża. Bishop Heidenreich of Bishopric of Chełmno received the Chełmno Land from the pope. The Polish duke Konrad I of Masovia turned possession of the settlement over to the bishop of Chełmno. This created a problem because the Teutonic Knights were in control of the Chełmno Land, and a dispute began between the Bishop of Chełmno and the Knights. The Pope at the time, Innocent IV, was not keen to continue the dispute and installed the Bishop as the rightful ruler of the settlement. This disagreement was the first historical mention of the settlement. In 1251, a large church, St. Simon and Judah, was built in the city.
 Link Information: none Answer: none
A:
How long did the Teutonic Knights control the Chelmno Land?