>Originally from Westphalia's German nobility, von Zass belonged to an ancient Westphalian family, whose representatives in the 15th century moved to the Baltic region, repeatedly raised weapons under the banners of the Order of the Sword, and in 1710, was among the 52 so-called chivalric families, including the Ungern-Sternbergs and Wrangel family, which took a solemn oath of allegiance to the Russian sovereign, Peter the Great.
>In 1830 Zass received command of the Mozdok Cossack Regiment as a result of his success in the Russo-Turkish War. With this regiment he undertook several successful expeditions against the Caucasian natives.
>In 1833, he was appointed commander of the Batalpashinsky section of the Kuban Line. Having studied the military traditions of Caucasian natives and having mastered the tactics of mountain warfare, he tried to seize the initiative and began to carry out regular preventive measures, based on data received from numerous scouts. Active defense was complemented by cruel punitive expeditions, which ended, as a rule, with the extermination of villages. He was appointed as chief commander and given full authority.[9]
>In 1834, Zass sent a report to Rosen detailing his campaign into Circassia: The savages panicked and started fleeing from their homes, leaving their weapons behind attempting to escape to the forest but most of them were killed by the Cossacks ... with the soldiers lined up ready to fight, the cleansing continued with artillery shells, and I sent there two infantry brigades, but they could only capture 11 more people, and since the fire was in flames in many places, the rest were either killed or burned after attempting to escape by hiding on the roofs of their homes or by the manure. So like this, we destroyed the neighborhood.
>Zass considered Circassians to be subhumans inferior to the "European Race", particularly Germans and Russians.[13][28][16][15][14][10][12] The only way to deal with the Circassians, in his opinion, was to scare them away "just like wild animals". He kept a box under his bed with his collection of severed Circassian body parts.[29]
>Zass advocated ruthless military methods predicated on this notion, including burning people alive, cutting off heads for enjoyment, burning populated villages to the ground, spreading epidemics on purpose, and mass rape of children.[9][30]
>Colonel Grigory Zass was a key figure in the Circassian genocide through ethnic cleansing, which included methods such as burning entire Circassian villages, and deliberately causing epidemics. Russian soldiers and Cossacks were paid for sending Circassian heads to Zass.[37] Zass then sent these severed Circassian heads to his friends in Berlin who were professors and used them to study anatomy.[32]
>Russians, following Zass' methods, raped Circassian girls during the 1877 Russo-Turkish war from the Circassian refugees who were settled in the Ottoman Balkans.[62][63]