Thomas is believed to have been born in the castle of Roccasecca
in the old county of the Kingdom of Sicily, which is now known
as the Lazio region of Italy, in 1225. His parents were well-off,
but as the youngest son Thomas was expected to enter the monastery.
At 5-years-old, Thomas began his education at Monte Cassino,
where he remained until the military conflict between Emperor Frederick II
and Pope Gregory IX reached the abbey. He was then
transferred and enrolled at the studium generale in Naples.
It is believed that Thomas was introduced to his philosophical
influences - Aristotle, Averroes, and Maimonides - at the university,
where he also met John of St. Julian, a Dominican preacher, who
influenced him to join the recently founded Dominican Order.
When Thomas' family learned of his decision, his mother Theodora
arranged for him to be moved to Paris. When Thomas was travelling to
Rome, his brothers captured him and returned him to their parents
at the castle of Monte San Giovanni Campano.
Thomas was held captive in the castle for one year as his family tried to
keep him from joining the Dominican Order. In the year he was held,
Thomas tutored his sisters and communicated with members of the Dominican Order.