The Mongols destroy the Khwarzin Dynasty and assume control over their territories. This marks the beginning of the Pax Mongolica, in which the trade centers of China and Europe are connected under Mongol rule, allowing for safe passage. The Mongol law, Yassa, helps create peace in the empire by forbidding blood feuds, adultery, theft, bearing false witness, and doing harm to the environment. Religious freedom is also allowed under the Yassa, possibly due to the sheer difficulty of requiring such a large empire to unite under one religion.