Jan of Tarnow founded the town of «Tarnopol» on April 15, 1540. After, locals have verbally adapted «Tarnopol» and renamed it to Ternopil.

The daughter of Hetman Jan of Tarnow Sophia of Tarnow got married to Prince Vasyl-Kostiantyn Ostrozkyi. She died early (she died during the birth of her youngest son Oleksandr), but survived her older brothers. That is why she became the heir to all paternal possessions and brought Ternopil to the possessions of the princes of Ostroh.