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

Passage: Irene was daughter of despotēs Theodore Komnenos Doukas, ruler of Epirus, and Maria Petraliphaina (sister of the sebastokratōr John Petraliphas). In 1230 Irene and her family were captured by the troops of tsar Ivan Asen II of Bulgaria in the battle of Klokotnitsa and they were taken in Tarnovo, where Irene grew up in the Palace. Irene became known for her beauty and the widowed tsar fell in love with her. They married in 1237. According to a Byzantine author, Ivan Asen II loved Irene "no less than Antony loved Cleopatra", and she may have been his mistress for some years before their marriage in 1237. By marrying Irene, Ivan Asen II would have broken church canons, as his daughter, Maria Asanina Komnena, from his marriage to Anna (Anisia) was married to Irene's uncle, Manuel of Thessalonica. There is some evidence that the Bulgarian church opposed the marriage and that a patriarch (called either Spiridon or Vissarion) was deposed or executed by the irate tsar.
 Link Information: Ivan Asen II, also known as John Asen II or John Asan II (, ; 1190s – May/June 1241) Answer: 40
Output:
At what age was Ivan Asen II of Bulgaria when his troops captured Irene and her family?