At the age of 16 he entered the Order of St. Dominic. Having become Archbishop of Florence (Communion), St. Antoninus excelled in his pastoral office by the austerity of his life, his charity and his sacerdotal zeal (Introit, Epistle, Alleluia). His prudence earned for him the title of "Antoninus of Counsel." He died rich in merits in 1459.
Statuit ei Dominus testamentum pacis, et principem fecit eum: ut sit illi sacerdotii dignitas in aeternum. * Memento Domine David et omnis mansuetudinis ejus.
The Lord made to him a covenant of peace, and made him a prince; that the dignity of the priesthood should be to him for ever. * O Lord, remember David: and all his meekness.
(Ecclus. 45:30 and Psalm 131:1. From the Introit at Mass).
May the merits, O Lord, of St. Antoninus, Thy confessor and bishop, avail us: that we who praise Thy glory in him, may likewise rejoice in Thy mercy towards us.
From the Catholic Encyclopaedia: http://www.newadvent.org/cathen/01585b.htm