Given the task definition and input, reply with output. This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.

Part of the Ottoman territories in the Balkans (such as Thessaloniki, Macedonia and Kosovo) were temporarily lost after 1402 but were later recovered by Murad II between the 1430s and 1450s. On 10 November 1444, Murad II defeated the Hungarian, Polish, and Wallachian armies under Władysław III of Poland (also King of Hungary) and John Hunyadi at the Battle of Varna, the final battle of the Crusade of Varna, although Albanians under Skanderbeg continued to resist. Four years later, John Hunyadi prepared another army (of Hungarian and Wallachian forces) to attack the Turks but was again defeated by Murad II at the Second Battle of Kosovo in 1448.
Who recovered Ottoman empire territories in the Balkans in the 1430s to the 1450s?