Tadeusz, who was given the name Andrzej Tadeusz Bonaventura Kosciuszko at his baptism, was the fourth child of Ludwik Tadeusz Kosciuszko and Tekla Ratomska Kosciuszko, coat of arms Roch III.
Tadeusz's father was a court official (swordsman) and the Lithuanian field roll regiment colonel.
Some sources claim Anna wished to be considered a product of her mother’s early marriage, so she claimed her father was a man named Pavel, who died when she was a toddler.
She claimed he was married to her mother before she married Matvej Pavlov.