 Complete the following phrase:  The Mongol forces approached Tabriz and got a ransom from the city in 1221. After destroying the city of Maragha, they attacked Diyarbakir and Ardabil and then again returned to Azerbaijan. Thus, the Mongols marched to the north, plundering Shirvanen route. In addition, Beylagan was plundered in the spring of 1221. This took them through the Caucasus into Alania and the South Russian steppes where the Mongols routed the Rus-Kipchak armies at the 