"If the great, the military leaders and the leaders of the many descendants of the ruler who will be born in the future, should not adhere strictly to the Yasa, then the power of the state will be shattered and come to an end, no matter how they then seek Genghis Khan, they shall not find him."
                    -GENGHIS KHAN

    Even before there was a Genghis Khan, the tribes of Mongolia had a common law.  The law was unwritten, and had showed variations for the various tribes.    As Genghis Khan grew in power and influence, a need arose for laws that the whole empire could use.  The Yasa was a written record of ancestral traditions, customs, laws, and Genghis Khan's ideas, which were added constantly during his lifetime.
    Anything that was written in the Yasa had to be followed exactly.  This resulted in strong discipline, which determined how the Mongols lived and interacted.  In 1246, a Franciscan monk John of Plano Carpini visited Mongolia and was impressed with how much discipline the Mongols had.  He claimed that the Mongols showed more obedience than in the clergy located in Europe.
    Genghis Khan was able to use obedience demanded from the Yasa to influence the morality of his people.  He could also influence the mentality of his people with his decisions.  The greatness that was achieved under his command resulted in the Mongols gaining self pride.
    When in the presence of Genghis Khan, you weren't allowed to exercise any power.  The only way that you could, was if you were his representative.
    There is no surviving manuscript of the Yasa today, nor has there been any document discovered describing it's contents.  So, assumptions must be made cautiously because there is no real certainty as to what was really written.  There is though, a few fragments written about the Yasa by Persian, Arabian, and Syrian historians after Genghis Khan's death.  The historian that might be the most important of the three is the Persian, Juvaini.  Yet it is probable that none of these historians actually did see a copy of the Yasa, which was written in the Uighur script.
    Even though the Yasa was started in 1206, it had to be added too to accommodate the needs of the growing Asian Empire.  The high cultural standard in China showed a heavy influence on the primitive tribes.  The expansion into China probably affected matters of law and order.  The Mongols were tolerant when it came to religious matters, and had no rules governing the slaughter of animals.  The ritual killing performed by the Muslims, therefore continued because a lack of a standard method.  Laws that were set up in Russian, Chinese, and Persian areas remained valid.  But the governors of the regions had to take into account the contents of the Yasa.
    There were many different punishments that the Mongols knew how to use, most of which were nothing more than torture.  When someone from the Golden Family (Genghis' Family) or someone from another princely house was condemned to death, no blood would be allowed to flow.  Some of the things that would be used in these situations was strangulation by bowstring or asphyxiation under a pile of carpet.  When convicted, the entire family of the accused, including women and children were executed, considered accessories to the crime.
    The daily life of the citizens were greatly impacted because of the harshness of the Yasa.  Among many of the tribes, adultery, robbery, plunder, and murder were very rare, unlike times before Genghis Khan, when crimes such as these were common.  Genghis Khan's intentions were to make the Yasa inviolable.  In order to uphold the Yasa, he gave his son Chaghatai, the responsibility of guarding it.  Genghis was smart by choosing this son of his because Chaghatai was stubborn, and a severe supported of the principles of his father's system.
    The Yasa, however did not survive for long with the nomadic tribes.  By the end of the thirteenth century, the influence, which once was so powerful, began to diminish.  The destruction of these laws came faster with the disintegration of the Empire.