St. Dominic, appointed in 1218, was the first Master of the Sacred Palace, the Papal Theologian. Eighty-four Dominicans consecutively succeeded him until the early 20th century.

In the Dominican Order he ranks next to the general, ex-general and vicar-general. He is ex-officio consultor of the Holy Office, prelate-consultor of Rites, and perpetual assistant of the Index. He is consultor of the Biblical Commission, and is frequently consulted on various matters by the pope as his theologian. His official audience occurs once a fortnight.

The official apartment of the Master of the Sacred Palace contains the unbroken series of portraits of the Masters of the Sacred Palace, from St. Dominic down.