Which religious order did St. Thomas Aquinas join as a young man?

St. Thomas Aquinas joined the Dominican order—a mendicant religious order founded by St. Dominic—in 1244 when he was approximately 20 years old.1

His decision to join the order was initially met with strong disapproval from his family, who kidnapped him and held him captive for about two years in an unsuccessful attempt to prevent him from pursuing his vocation. Following his eventual liberation, he continued his studies and became a prominent figure within the order, eventually teaching theology at the University of Paris.12