Cardinal Francis Xavier Nguyen Van Thuan was never charged with a crime, yet he was held in a Vietnamese prison for thirteen years, nine of which were spent in isolation.
During that time, alone in his cell, he would celebrate Holy Mass with a few drops of wine sent to him by friends, and tiny pieces of bread.
Over the years, Van Thuan’s guards would need to be replaced because they kept converting to Catholicism due to his witness.
Read more about Cardinal Van Thuan’s solitary Masses, here