http://warandgame.wordpress.com/2007/12/13/muscovite-boyar-late-sixteenth-century/
From the second half of the fifteenth century, a growing role in the Russian army was assigned to the nobility (boyars), who were bound to service by possession of fiefs. This system in the armed forces became particularly strong during the rule of Ivan IV (’the Terrible’, 1530-84). Reforms carried out in the mid-sixteenth century tied the small nobility to the emperor (tzar) by the granting of fiefs. These men were the foundation for increasing absolutism. As early as 1550, a special caste of nobles under military obligation was formed; 1,078 of them were given land around Moscow, and these were the ‘chosen one thousand’, landowners directly dependent on the emperor. Army officers were recruited from among their ranks; nobles under military obligation from other parts of the country, who were the majority, held subordinate positions and were called ‘city obligators’.
Noblemen made up the cavalry, which numbered about 25,000 towards the end of the sixteenth century; in times of war, this could increase to 40-50,000. In appearance, Russian cavalry followed the eastern pattern. Mail or plate armour was worn, with eastern-type helmets and forearm vambraces; retainers did not have this protective equipment, but wore padded clothes which could stop an arrow. Fur and silk and jewels were worn, while the armour was richly ornamented with inlays; sometimes, the mail was made of silver. Weapons included lances, javelins, scimitars, maces, and, in the late sixteenth century, pistols. The principal weapon, however, was the composite bow.
Russian cavalrymen rode jockey-style, with knees drawn up, which largely determined their tactics. This position was ideal for the archer, but unsuited to receiving a lance blow. Russian horses were wiry, but small, and this was another reason for the avoidance of frontal charges. Tactics were surprise and numerical superiority, which enabled them to surround the enemy and fire from a distance, avoiding close combat. Discipline was somewhat lacking, but the men were loosely organized into squadrons (100) and regiments (1,000). Several regiments made up a division (polk), of which there were six: van (perodovoi polk), left (levoi polk) and right (pravoi polk) wings, main body (bolsoi polk), reserve (smorozevoi polk) and a kind of light cavalry unit detached forward for skirmishing and reconnaissance (ermaulni polk). Each division had its own pennant of St George.