Voivodes of the Polish–Lithuanian Commonwealth were one of the highest ranking officials who could sit in the Senate of Poland. They were the officials in charge of the voivodeships (provinces/palatinates) of the Polish–Lithuanian Commonwealth. The office first appears as Palatine (Palatinus) who was the first person after the King. As Poland broke into separate principalities each Prince had his court and his own Palatine. When the Kingdom was (partially) reunited the Palatines became heads of the former Principalities now turned into Palatinates. As such they were members of the King's council (comites palatini). The title got merged with the Polish Wojewoda (Slavic Woi-woda/вои-вода (Cyrillic) consists of two parts with meaning army or war and guide or direct and it is a lexical and institutional equivalent of the Latin Dux Exercituum and the German Herzog all meaning "leader of the army"). The difference between Wojewoda and Herzog is that Herzog, after being a rank appointed by the Monarch became a hereditary title of honour, while Wojewoda remained appointed for life and continued as a real-power position before it also lost meaning to the Starostas. Polish historians still use Palatyn and Wojewoda as synonyms.
The competences of voivodes varied, as they were influenced by historical precedents related to their voivodeships. The smallest were those of the voivodes in Halych Ruthenia (Ruś Halicka), the largest those in the Royal Prussia (Prusy Królewskie). Those competences changed in time as well.
The office was created in the Kingdom of Poland under Piasts, and from the Crown of the Polish Kingdom spread to Grand Duchy of Lithuania after 1569 as an overseer of voivodeship and its administration, but the effectiveness and real powers of this office decreased, so that in the Kingdom of Poland under Jagiellons it was a much less significant post. In the realm of the military, voivodeship retained just the role of the leader of pospolite ruszenie. Administrative competences were limited to the role of Marshal of the sejmik, but even that disappeared by the time of the Commonwealth. His control over the cities was mostly an honorary function, as formally it was the competence of the starost. One of the few competences that voivodes retained throughout history was the power to set and enforce prices (although in fact this competence was delegated to the sub-voivode (podwojewoda)).