Pope Eugene IV, Council of Florence, Session 11, Feb. 4, 1442, ex cathedra: “Regarding children, indeed, because of danger of death, which can often take place, when no help can be brought to them by another remedy than through the sacrament of baptism, through which they are snatched from the domination of the Devil [original sin] and adopted among the sons of God, it advises that holy baptism ought not be deferred for forty or eighty days, or any time according to the observance of certain people…” (Denz. 712)

Pope Martin V, Council of Constance, Session 15, July 6, 1415 – Condemning the articles of John Wyclif – Proposition 6: “Those who claim that the children of the faithful dying without sacramental baptism will not be saved, are stupid and presumptuous in saying this.”- Condemned (Decrees of the Ecumenical Councils, Vol. 1, p. 422.)

Pope St. Zosimus, The Council of Carthage, Canon on Sin and Grace, 417 A.D.- “It has been decided likewise that if anyone says that for this reason the Lord said: ‘In my Father’s house there are many mansions’ [John 14:2]: that it might be understood that in the kingdom of heaven there will be some middle place or some place anywhere where the blessed infants live who departed from this life without baptism, without which they cannot enter into the kingdom of heaven, which is life eternal, let him be anathema.” (Denzinger 102, authentic addition to Can. 2.)