Let me remind you of an interesting Graeco-Latin metre: the trochaic tetrameter catalectic. You should be equipped with this information, because it is the metre of the two great Pange lingua hymns used in the Holy Week Liturgy: the one about the Cross, written by Venantius Fortunatus for a royal Mother Superior who had succeeded in begging a Relic of the True Cross from the Emperor in Constantinople; we sing that on Good Friday at the Liturgy of the Cross (and in the Divine Office). The other, written by S Thomas Aquinas for Corpus Christi, is sung as the Most Holy is taken to Altar of Repose on Maundy Thursday. But this metre got its first recorded Christian use in the hymn Corde natus ex Parentis, often used at Christmas, centonised from (i.e. made up of extracts from) the Cathemerinon of Prudentius (348-c410).
Tumpty is a trochee; two of them, tumpty tumpty, make up a 'trochaic metron'; four of these are described as a trochaic tetrameter; and if you chop off the very last syllable of the sixteen, what's left is a trochaic tetrameter catalectic. (Some people call it a trochaic septenarius, but then, they would, wouldn't they.) The line is very long, and, since there is a regular word-break after the eighth syllable, printers commonly split it up into two lines respectively of eight and of seven syllables.
What is surprising about this metre is that it was seen and used by the ancients as comic and vulgar (and so described, kordakikoteron, by Aristotle ... the kordax was a very obscene dance). It is used by the great writer of New Comedy, Menander (you could go and see a nice bust of him among the Howard marbles in the Ashmolean; he more or less invented the 'situation comedy' and perfected the eternally fertile formula 'Boy loves Girl: there is an Obstacle: the help of a Clever Slave solves it so that all live Happily Ever After'). In one of his 'latest' plays ('latest' in the sense that lost plays keep turning up on papyri preserved in the dry sand of the Egyptian desert), the Girl from Samos, it is used in a hilarious slapstick scene featuring Girl's comically nasty Father, Niceratus. Menander's Roman imitators adapted it into Latin, and so Plautus uses this metre in his Mostellaria for the scene where Boy, drunk, comes across Girl while she is putting her make-up on and goes for an inopportune contact.
So how did this frivolous, indeed indecent, metre come to be used for what we might think of as the stateliest and most dogma-laden hymns of our Latin tradition? One possibility: Think Roman Squaddies. Think Roman Squaddies in a happy mood, particularly after a great victory; they have returned to Rome; the Senate has voted a Triumph; and so the troops, heavy with gold and alcohol, are singing in the Triumph Procession as they process behind their general. You may be surprised by this; but they are singing obscene songs insulting the general, probably to avert from him divine jealousy. And Suetonius preserves for us three lines in just this metre which were sung during C Iulius Caesar's Gallic triumph (interesting that, just as with the Christian hymnographers, three lines seem to make up a stanza):
Gallias Caesar subegit, Nicomedes Caesarem:
Ecce Caesar nunc triumphat qui subegit Gallias;
Nicomedes non triumphat qui subegit Caesarem.
Which is best left untranslated; well, anyway, I am going to leave it untranslated. And so, turning now to the Christian hymnwriters, we find the sense of military triumph already vividly present in one of Prudentius' stanzas:
Solve vocem mens sonoram, solve linguam mobilem,
Dic tropaeum passionis, dic triumphalem crucem,
Pange vexillum, notatis quod refulget frontibus*.
This, of course, is the inspiration of Venantius Fortunatus' first stanza (and, indeed, of his hymn Vexilla Regis):
Pange lingua gloriosi proelium certaminis,
Et super crucis tropaeo dic triumphum nobilem,
Qualiter redemptor orbis immolatus vicerit.
The idea is of the Tree of the Cross as the tropaion [trophy], i.e. the battlefield Tree upon which the rejoicing soldiery hung the spoils (mainly armour) looted from their defeated enemies. It is both clever and appropriate; compare S Paul (Colossians 2:14-15) proselosas auto toi stauroi; apekdusamenos tas archas ... thriambeusas autous en autoi. No wonder Venantius Fortunatus thought the idea, and the metre, appropriate to express the exuberant joy of processing into Poitiers with a Relic of the Redeeming Tree.
And is there not a whiff of a Triumph Procession as the priest bends the ends of the Humeral Veil over the ciborium containing God's Body and then carries It through the adoring People of God?
*Literally: Loose, O mind, the sonorous voice, loose the mobile tongue, speak the trophy of the Passion, speak the triumphal Cross, sing the banner which shines on marked foreheads [referring to the Cross marked on the foreheads with Chrism at Confirmation/Consignation].