To understand the similarities that Mongols and Europeans shared, it is necessary to look at what virtues the two cultures felt should be rewarded. Both cultures extolled the virtues of obedience to the law and discipline in their military ranks. While most would view Mongols as uncivilized hordes of warriors, obedience and submission to the law were viewed as necessary in their society. Rule of law was introduced by the Romans and existed in Europe long after the fall of Rome to the barbarian tribes of the frontiers.
Chivalry was a code that was expected to be followed by the knights of Europe. Important tenets of chivalry included courage, honor, and loyalty. These same qualities existed in the armies of Genghis Khan and his successors. There are accounts of Khan allowing his enemy to live if he felt that the person was extremely loyal to his king or troops. One of Khan's closest advisors was allowed to serve because he had actually shot Genghis with an arrow in battle. Khan rewarded this man because of his skill and courage in battle.
Another similarity in the two cultures was the use of violence to achieve their goals. Europeans and Mongols both believed in the acquisition of territory through violence and conquest. This concept of "might makes right" is witnessed throughout the history of Europe and certainly during the period of Mongol conquest.