At what point in their theological career did each decide to 'take up a serious religious life'? It appears it was well after each became a prince of the church.
Generally when they decided to become Priests.
It appears it was well after each became a prince of the church.
I'd encourage you to find proof of this from some source other than the incestuous writing of historians quoting each others books. Historians who have studied the original sources tend to not support the wild charges thrown about.