What are the doors on side altars for? I am referring to the lockable door that is in the center of the side altar in old churches.
Did the priest use it in his private Mass (before V2 when there was no concelebration) to temporarily hold the Eucharist until he was finished with Mass, when he then transferred hosts he consecrated to the main tabernacle? Or was it to store the chalices and ciborium for Masses said at that altar?
Sorry if this is a brain dead question, I am really just curious about why old churches are setup the way they are. I didn’t think they would have three tabernacles, surely they only used the main altar for that?