By the end of the month, the Peloponnese was in open revolt against the Ottomans and by October 1821 the Greeks under Theodoros Kolokotronis had captured Tripolitsa. The Peloponnesian revolt was quickly followed by revolts in Crete, Macedonia and Central Greece, which would soon be suppressed. Meanwhile, the makeshift Greek navy was achieving success against the Ottoman navy in the Aegean Sea and prevented Ottoman reinforcements from arriving by sea. In 1822 and 1824 the Turks and Egyptians ravaged the islands, including Chios and Psara, committing wholesale massacres of the population. This had the effect of galvanizing public opinion in western Europe in favor of the Greek rebels.[page needed]

Answer this question, if possible (if impossible, reply "unanswerable"): In what year did the Greeks take Tripolitsa?
1821