The Ternopil Castle is a stronghold which gave birth to the city of Ternopil. It was built in the 16th century to protect the southern border of the Kingdom of Poland and the Polish-Lithuanian Commonwealth.
The castle originated as the residence of a Polish nobleman, Jan Amor Tarnowski, in 1540. Construction works (1540–1548) on the marshy bank of the Seret River were authorized by King Sigismund the Old. The castle, around which the modern town has developed, was encircled by a wooden fence and a deep moat. The latter was connected in 1548 to the castle pond.