I couldn’t find an official exhaustive list of saints from the Vatican or Holy See, so if anyone can link me to it. I don’t know if he was a saint In the Catholic Church because there are conflicting sources on the internet like here https://www.newadvent.org/cathen/04295c.htm and here https://www.catholic.org/saints/saint.php?saint_id=2731, but Catholic Answers does not give him the title of saint - https://www.catholic.com/encyclopedia/constantine-the-great. I’ve recently been reading about Constantine the great. I won’t lie I was displeased that his 11-year old nephew and brother-in-law Licinius were killed after initially forgiving him. But who am I to judge, God knows, as he was baptized on his deathbed and the past is the past. I was curious, Are there other saints who committed grave sins while emphasizing Christian virtues?
I don’t think Constantine was ever canonized by the Roman Catholic Church, it was the East who did so, but considering that includes Eastern Catholics he could be considered a Saint among Westerners as well.
With the grave matter and Saints question, while examples of a pre-conversion Saints committing grave sins abound (St. Augustine, St. Margaret of Cortana, most likely a ton of other saints) I can’t think of an example of a saint greviously sinning post-conversion, which makes sense given that canonized saints exude great values in their earthly life, there probably are examples. Saints weren’t perfect, and all of them (except Our Lady) have committed some kind of sin, mortal or otherwise.
It depends what you consider to be 'conversion '. St Teresa of Avila was in her 40s before her heart really caught on fire. The convent she was at had some pretty serious problems, including young men writing romantic letters to some of the nuns. It was largely privileged Spanish women who continued to live somewhat luxuriously in their housing. I don’t think she was involved in that but the heroic virtue didn’t come until much later in life.
St. Matthew is an excellent of a scoundrel turned saint. When he met Jesus, Matthew was a tax collector. He lined his pockets by making people pay more than they owed to the Romans.
Still, Our Lord selected Matthew to become one of the 12 Apostles and an evangelist.
Sinners who became saints show us that we all have a shot at holiness, no matter what we’ve done.
9 As Jesus passed on from there, he saw a man named Matthew sitting at the customs post. He said to him, “Follow me.” And he got up and followed him.
10 While he was at table in his house, many tax collectors and sinners came and sat with Jesus and his disciples.
11 The Pharisees saw this and said to his disciples, “Why does your teacher eat with tax collectors and sinners?”
12 He heard this and said, “Those who are well do not need a physician, but the sick do.
13 Go and learn the meaning of the words, ‘I desire mercy, not sacrifice.’ I did not come to call the righteous but sinners.”
St. Helena, Constantine’s mother, is a saint in the Western Church, but Constantine himself is a saint only in the Orthodox churches. If you’re interested in finding out more about him, several important new books have appeared in recent years, including these two:
He is venerated as a saint in some of the Eastern Catholic Churches as well.