Guards (Russian: гвардия) or Guards units (Russian: гвардейские части, 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 Marksman Troops (Стрелецкое Войско), the Muscovite harquebusiers formed by Ivan the Terrible by 1550.