Guards () or Guards units (, gvardeyskiye chasti) were elite military units of Imperial Russia prior to 1917–18. The designation of Guards was subsequently adopted as a distinction for various units and formations of the Soviet Union and the modern Russian Federation. The tradition goes back to a chieftain's druzhina of medieval Kievan Rus' and the streletskoye voysko (Стрелецкое Войско), the Muscovite harquebusiers formed by Ivan the Terrible by 1550. The exact meaning of the term "Guards" varied over time. Imperial Russian Guard In the Russian Empire, Imperial Russian Guard units (also or life-guard, ), derived from German Leibgarde (en: lifeguard or life-guard), were intended to ensure the security of the sovereign, initially, that of Peter the Great in the 1690s. These were based on the Prussian Royal Life Guards. During the 19th century the Imperial Russian Guard regiments were not exclusively composed of Russian troops, but also included Lithuanian, Finnish and Ukrainian units. At the beginning of the 20th century, the Imperial Guards consisted of 13 infantry, 4 rifles and 14 cavalry regiments, artillery, engineers and transport, making up a separate entity within the army of three divisions. During the Brusilov Offensive the 1st and 2nd Guards' numbers were supplemented with line army corp and from September 1916 were known as the 'Special Army'. In February–March 1917, the defection of reserve battalions of the Imperial Guard based in St.Petersburg was a major factor in the overthrow of the Tsarist government. The service units of the Guard at the front disintegrated along with the remainder of the Imperial Army, until it was formally replaced by the new Red Army on 28 January 1918. Russian Revolution The Red Guards () were armed groups of workers formed during the Russian Revolution of 1917, although the designation and concept dates back to Moscow during the Revolution of 1905. In 1917 the volunteers of the Red Guard and their elected leaders formed the main strike force of the Bolsheviks. These workers' militias were created in March 1917 in by Factory and Plant Committees and by Bolshevik party cells, with the initial purpose of defending the industrial enterprises and districts where they were recruited. In October 1917 the Red Guards of Petrograd played a leading role in the capture of the Winter Palace and the overthrow of the Provisional Government. When the Soviet Red Army was formed in 1918, the Red Guards became the Army