Saint Antoninus (ăntōnī´nəs), 1389–1459, Italian churchman, b. Antoninus Pierozzi. He was a Dominican and became archbishop of Florence. He ruled well and was renowned for his charitable work in the city. His Summa moralis is a pioneering work in moral theology, of interest for its treatment of commercial ethics and the morality of banking. It is a valuable record of the effect the new economic changes were having on everyday life. Feast: May 10.