Офицеры Лб.-гв. Казачьего полка, 1903

The Cossacks were a group of predominantly East Slavic-speaking people who lived in the lands of the Dnieper, Don, Terek, and Ural rivers in Eastern Europe. The Cossacks were known for their military skills and their semi-nomadic lifestyle. They were organized into autonomous communities and were known for their martial traditions and their resistance to foreign domination. The Cossacks played an important role in the history of Eastern Europe, and they were involved in many conflicts and wars throughout their history. Today, the Cossacks are still recognized as a distinct cultural group in some parts of Eastern Europe. Cossacks had a tradition of independence and finally received privileges from the Russian government in return for military service. Originally (in the 15th century) the term referred to semi-independent Tatar groups, which formed in the Dnieper region. The term was also applied (by the end of the 15th century) to peasants who had fled from serfdom in Poland, Lithuania, and Muscovy to the Dnieper and Don regions, where they established free self-governing military communities. In the 16th century, there were six major Cossack hosts: the Don, the Greben (in Caucasia), the Yaik (on the middle Ural River), the Volga, the Dnieper, and the Zaporozhian (mainly west of the Dnieper).

The Imperial Russian Army was the land armed force of the Russian Empire, active from around 1721 to the Russian Revolution of 1917. In the early 1850s, the Russian army consisted of around 938,731 regular soldiers and 245,850 irregulars (mostly Cossacks).