Mikoà Âaj Hieronim Sieniawski (1645–1683) was a Polish noble (szlachcic), military leader and politician.
He was the son of the starost of Lwów Adam Hieronim Sieniawski and Wiktoria Elà ¼bieta Potocka, the daughter of Hetman Stanisà Âaw "Rewera" Potocki. He married in 1662 the daughter of Court and Grand Marshal Prince Aleksander Ludwik Radziwià Âà Â, Princess Cecylia Maria Radziwià Âà Â.
He was Grand Guardian of the Crown since 1666, Great ChorÃ à ¼y of the Crown since 1668, Court Marshall of the Crown since 1676, starost of Lwów since 1679, voivode of Volhynian Voivodship since 1679, Field Crown Hetman since the beginning of 1683 and starost of Radom, Rohatyn, and Piaseczno.
He became famous as a talented commander in wars against Cossacks and Tatars during the reign of King John II Casimir. In the rank of a ChorÃ à ¼y, he took part in the Battle of Chocim in 1673, alongside John Sobieski.
He was Marshal of the Coronation Sejm between 2 and 14 March 1676 in Kraków.
Like his son Adam Mikoà Âaj Sieniawski, he participated in the Battle of Vienna in 1683. He fell ill the same year with dysentery and died on his return to Poland on 15 December 1683 in Lubowla, at the age of 38.