Hetman was the title of the second highest military commander (after the monarch) used in 15th to 18th century Poland, Ukraine and Grand Duchy of Lithuania, known from 1569 to 1795 as the Rzecz Pospolita.
This title was used among the Cossacks (гетьман) of Ukraine since the 16th century and by the Czechs (hejtman) in Bohemia from the Hussite Wars (15th century) onward. Hejtman is today the term for the elected governor of a Czech region (kraj). Hetman is also the Polish name for the chess queen.
The word is probably derived from German > OHG Hauptmann, with Haupt meaning "main" or "head" and Mann meaning "man". Hauptmann was a common military title during the medieval times meaning "captain" but more corresponding to today's "general". German "Hauptmann" being derived from the Polish "Hetman/Hatman" is less likely. Due to centuries of contact, Poland and Prussian states were influenced by each other's military traditions (see also Rittmeister/rotmistrz) or administrations (Rathaus/ratusz, Bürgermeister/burmistrz). However, an intermediary might have been provided by Czech.
The first Polish title of Grand Crown Hetman was created in 1505. The title of hetman was given to the leader of Polish Army and until 1581 the hetman position existed only during the specific campaigns and wars. After that, it became a permanent title, as were all the titles in Kingdom of Poland and Polish-Lithuanian Commonwealth. At any given time there were four hetmans – great and field (deputy) for each Poland and Lithuania. The title couldn't be taken away unless treachery was proven (from 1585). Thus in effect most hetmans served for life, as illustrated by the case of Jan Karol Chodkiewicz literally commanding the army from his deathbed. Hetmans were not paid for their job by the Royal Treasury. Hetmans were the main commanders of the military forces, second only to the monarch in the army's chain of command. The fact that they could not be removed by the monarch made them very independent, and thus often able to pursue independent policies. This system worked well when a hetman had great ability and the monarch was weak, but by the same token it sometimes produced disastrous results in the opposite case, as illustrated by the actions of Mikołaj Potocki in 1648. The contrast with states bordering the Commonwealth, where army commanders could be dismissed at any time by their sovereigns, was immense.
The reform in 1776 limited the powers of the hetmans. The hetman office was abolished after the third partition of Poland in 1795.
At the end of the sixteenth century, the commanders of the Zaporizhian Cossacks were called Koshovyi Otaman or hetman (for example: Christof Kosynsky - first zaporizhian hetman ). In 1572, the hetman was a commander of the Registered Cossack Army (Реєстрове козацьке військо) of the Rzecz Pospolita too. From 1648, the start of Bohdan Khmelnytsky's uprising, a hetman was the head of the all Ukrainian State - Hetmanshchyna. Although they were elected, Ukrainian hetmans had very broad powers and acted as the heads of the Cossack state, its supreme military commander, and the top legislator (by issuing administrative decrees).
After the split of Ukraine along the Dnieper River by the 1667 Polish-Russian Treaty of Andrusovo, Ukrainian Cossacks (and Cossack Hetmans) became known as Left-bank Cossacks (of the Cossack Hetmanate) and Right-bank Cossacks.
In the Russian Empire, the office of Cossack Hetman was abolished by Catherine II of Russia in 1764. The last hetman of the Zaporozhian Army (the formal title of the Hetman of Ukraine) was Kyrylo Rozumovsky (1728-1803) who reigned 1751-1764.
The title was revived in Ukraine during the revolution of 1917 to 1920. In early 1918, a conservative German-supported coup overthrew the radical socialist Ukrainian Central Rada and its Ukrainian People's Republic and established a "Hetmanate" or monarchy headed by Pavlo Skoropadsky who claimed the title "Hetman of Ukraine". This regime lasted until late 1918 when it was overthrown by a new "Directory" of the re-established Ukrainian People's Republic.