Yassa, alternatively Yasa, was the written code of law created by Genghis Khan It was in force in the Mongol empire. Genghis Khan appointed his son Chagatai (later Chagatai Khan) to oversee the execution of it.
The document is extremely comprehensive and very specific. For example, it outlines laws for various members of the community like soldiers, officers, doctors, etc. Death was the punishment for minor offenses: a soldier not picking up the stuff that falls from the person in front of him would be put to death.
The main purpose of the document was to eliminate social and economic issues and disputes that existed among the Mongols before the unification by Genghis Khan. It was revised constantly as needs arose.
Yasa's mother was the first to notice the absence of her son and she reported the matter to her husband.
Venerable Yasa's mother and his former wife heard the doctrine expounded by the Buddha and, having attained the first stage of Sainthood, became His first two lay female followers.
Venerable Yasa's parents and his former wife, for instance, were the foremost lay followers of the Buddha.