Mikołaj Sieniawski (c. 1489[1] – 1569[2]) was a notable Polish magnate, military commander and a prominent politician of his times.
He built stone Brzeżany Castle round which the modern town of Berezhany has developed.
[3] Since 1539 Mikołaj Sieniawski served as a Field Hetman of the Crown[4] and took part in most wars Poland was engaged in.
He took part in the battle of Obertyn in 1531, under hetman Jan Tarnowski,[5] from whom he adopted the clan crest of Leliwa.
In 1563 he was promoted to the rank of Grand Crown Hetman, that is the de facto commander in chief of the Polish army.