Complex sentence: He launched a military campaign into Tibet under the command of Generals Lichi and Dhordha, and the marauding Mongols burned down Tibetan monuments such as the Reting monastery and the Gyal temple in 1240.
Split into simpler sentences: He launched a military campaign into Tibet under the command of Generals Lichi and Dhordha. The marauding Mongols burned down Tibetan monuments such as the Reting monastery and the Gyal temple in 1240.