C.S. Lewis writing about the Middle English word ‘solempne’:
This means something different, but not quite different, from modern English solemn. Like solemn it implies the opposite of what is familiar, free and easy, or ordinary. But unlike solemn it does not suggest gloom, oppression, or austerity. The ball in the first act of Romeo and Juliet was a ‘solemnity’. The feast at the beginning of Gawain and the Green Knight is very much of a solemnity. A great mass by Mozart or Beethoven is as much a solemnity in its hilarious Gloria as in its poignant crucifixus est. Feasts are, in this sense, more solemn than fasts. Easter is solempne, Good Friday is not. The Solempne is the festal, which is also the stately and the ceremonial, the proper occasion for pomp – and the very fact that pompous is now used only in a bad sense measures the degree to which we have lost the old idea of ‘solemnity’. To recover it you must think of a court ball, or a coronation, or a victory march, as these things appear to people who enjoy them; in an age when every one puts on his oldest clothes to be happy in, you must re-awake the simpler state of mind in which people put on gold and scarlet to be happy in.
Above all, you must be rid of the hideous idea, fruit of a wide-spread inferiority complex, that pomp, on the proper occasions, has any connexion with vanity or self-conceit. A celebrant approaching the altar, a princess led out by a king to dance a minuet, a general officer on a ceremonial parade, a major-domo preceding the boar’s head at a Christmas feast – all these wear unusual clothes and move with calculated dignity. This does not mean that they are vain, but that they are obedient; they are obeying the hoc age which presides over every solemnity. The modern habit of doing ceremonial things unceremoniously is no proof of humility; rather it proves the offender’s inability to forget himself in the rite, and his readiness to spoil for every one else the proper pleasure of ritual.
— A Preface to Paradise Lost.