I understand that if one were to go back in time and ask a participant at the battle of Agincourt what the date was, he would (if he knew) say that it was the 16th of October, he would also (more likely) say that it was — famously — St Crispin's Day:
This day is call’d the feast of Crispian.
He that outlives this day, and comes safe home,
Will stand a tip-toe when this day is nam’d,
And rouse him at the name of Crispian.
Currently, of course, we celebrate the anniversary of the event today, on the 25th of October — but we also call this day St Crispin's Day.
Did the dates of Saints Days move with the Gregorian calendar reforms? If so was this move done consistently, and at the time of the reforms or later?