 Complete the following phrase:  Anis long-term decline began in 1239 when Mongols sacked the city and massacred its population. In 1319 a devastating earthquake struck Ani. It resulted in the collapse of the cathedrals conical roof. Ani was completely deserted by the 18th century. The drum reportedly collapsed during an 1832 or 1840 earthquake. The north-western corner of the cathedral was heavily damaged by a 