Voyi

Armies of Ukraine
Kyivan Rus' Druzhyna (862–1240)
Kingdom of Galicia–Volhynia Voyi
Polish–Lithuanian Commonwealth Registered Cossacks Zaporozhian Cossacks (1492–1648)
Zaporizhian Host Zaporozhian Cossacks (1648–1775)
Austria-Hungary Legion of Sich Riflemen (1914–1918)
Ukrainian People's Republic Ukrainian People's Army (1917–21) Sich Riflemen (1917–21) Ukrainian Galician Army (1918–19)
Free Territory Revolutionary Insurrectionary Army (1918–1921)
Carpatho-Ukraine Carpathian Sich (1938-39)
Ukrainian National Government UPRA (1941–1944) Ukrainian Insurgent Army (1941–1955)
Ukrainian SSR Red Cossacks uk (1918–19) none (1919–1991), part of the Soviet Armed Forces
Ukraine Armed Forces (1992–Present)

Voyi (singular voi or voy) was a category of armed forces in ancient Rus.

Unlike the standing force druzhina, voi force was drafted from a local population. Next to the druzhina, the voyi formed a basis of an army in Rus'. A Voivode (voi - "army", vode - "to lead", meaning "Warlord") was appointed by a prince (knyaz) in charge of them.