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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.

All Greeks were united, however, in their determination to liberate the Greek-speaking provinces of the Ottoman Empire, regardless of the dialect they spoke. Especially in Crete, a prolonged revolt in 1866–1869 had raised nationalist fervour. When war broke out between Russia and the Ottomans in 1877, Greek popular sentiment rallied to Russia's side, but Greece was too poor, and too concerned of British intervention, to officially enter the war. Nevertheless, in 1881, Thessaly and small parts of Epirus were ceded to Greece as part of the Treaty of Berlin, while frustrating Greek hopes of receiving Crete.
Output:
War between Russia and the Ottomans began in what year?