You can rename the months any time you feel like. The problem is getting other people to go along with your renaming.
Once upon a time, enough people cared what the Pope had to say, he could actually succeed in changing the calendar for everybody. But, it would be a rather interesting future history for the Catholic Church to regain power to the point that became true once again.
Once upon a time, enough people cared what the Pope had to say, he could actually succeed in changing the calendar for everybody. But, it would be a rather interesting future history for the Catholic Church to regain power to the point that became true once again.