Mongol invasions and conquests

"... after they had besieged the city for a long time, they took it and put the inhabitants to death. When we were journeying through that land we came across countless skulls and bones of dead men lying about on the ground. ... the Tartars destroyed the whole of Russia."

"I have been avoiding mentioning this event for many years because I consider it too horrible. ... a group of friends urged me to record it since I knew it first-hand. Then I saw that to refrain from it would profit nothing. Therefore, we say: this deed encompasses mention of the greatest event, the most awful catastrophe that has befallen time. It engulfed all beings, particularly the Muslims. Anyone would be right in saying that the world, from the time God created humans until now, has not been stricken by its like. Histories contain nothing that even approaches it."

"Kolya believed that the Mongols’ expansion was pathological. It was a ghastly spiral of positive feedback, born of Genghis Khan’s unquestioned military genius and fueled by easy conquests, a plague of insanity and destruction that had spread across most of the known world."