St. Robert Bellarmine, Doctor of the Church (16th century): De Sacramento Baptismi, cap. 6: “...among the ancients this proposition was not so certain at first as later on: that perfect conversion and repentance is rightly called the Baptism of Desire and supplies for Baptism of water, at least in case of necessity”....."it is certainly to be believed that true conversion supplies for Baptism of water when it is not from contempt but through necessity that persons die without Baptism of water.”
The Church Militant (De Ecclesia Militante), c. 3: "I answer therefore that, when it is said outside the Church no one is saved, it must be understood of those who belong to her neither in actual fact nor in desire [desiderio], as theologians commonly speak on baptism. Because the catechumens are in the Church, though not in actual fact, yet at least in resolution [voto], therefore they can be saved."
The Church Militant De Ecclesia Militante, c. 3: "Concerning catechumens there is a greater difficulty, because they are faithful [have the faith] and can be saved if they die in this state, and yet outside the Church no one is saved, as outside the ark of Noah…"
The Church Militant (De Ecclesia Militante), c. 2: "Others, however, are of the soul but not of the body (of the Church), as Catechumens and those who have been excommunicated, who may have faith and charity which is possible."
De Controversiis, “De Baptismo,” Lib. I, Cap. VI: “But without doubt it must be believed that true conversion supplies for Baptism of water when one dies without Baptism of water not out of contempt but out of necessity... For it is expressly said in Ezechiel: If the wicked shall do penance from his sins, I will no more remember his iniquities...Thus also the Council of Trent, Session 6, Chapter 4, says that Baptism is necessary in fact or in desire (in re vel in voto)”