She was the daughter of Katarzyna Sobieska, who was the sister of Jan III Sobieski, the king of The Kingdom of Poland and the Grand Duchy of Lithuania.

Her father was Władysław Dominik Zasławski, a Polish nobleman of Ruthenian stock of the house of Ostrogski, one of the richest magnates in Poland.

[3][4] After the death of her brother, Aleksander Janusz Zasławski in 1673, she became the only heir to one of the largest estates in the Commonwealth, the Ostrogski Ordination.

[5] This ordination was the largest one in the Volhyn, accounting for 11,000 square kilometres (4,200 sq mi) – about a third of the Volhynian Voivodeship – with over 1,000 settlements, including several dozen towns.

[citation needed] Prince Józef Karol Lubomirski had an ongoing extramarital affair which became public, resulting in Teofila's attempt at declaring him legally insane.