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.

France used the right moment and occupied Alger in 1830. In 1831 Muhammad Ali of Egypt, who was the most powerful vassal of the Ottoman Empire, claimed independence. Ottoman forces were defeated in a number of battles, and Egyptians were ready to capture Constantinople, which forced the sultan Mahmud II to seek for Russian military aid. 10 000 Russian army corps landed on the Bosphorus shores in 1833 and helped to prevent the capture of Constantinople, thus the possible disappearance of the Ottoman Empire was prevented.
In what year did France move into Alger?