So holy is this day of days

A sequence found about the same date is called in old manuscripts

THE COMMON MAN'S PROCESSIONAL.

So holy is this day of days No man can fill its meed of praise, Since the Holy Son of God Now hath conquered Death and Hell, And bound the Devil who there doth dwell, So hath the Lord delivered Christendom; This was Christ Himself: Kyrie Eleison!

Also heilig ist der Tag