sentences:  This time, his campaigning in the central Asia (today's central Kazakhstan) against the Khanates of Khiva and Kokand proved much more successful.After his troops successfully took the Kokand fortress of Ak-Mechet in 1853, the fort was renamed Fort-Perovsky after him.His military successes forced the Khanate of Khiva to make concessions in the 1854 treaty with the Russia Empire.