Palm Sunday: Gloria, laus et honor tibi ("All Glory, Laud, and Honor")

Gloria, laus is the Palm Sunday Hymnus ad Christum Regem ("Hymn to Christ the King") sung during the procession of the Liturgy of the Palms. It's a gorgeous chant:



Here's the chant score from the Brazilian Benedictines:

There is of course a more recent hymn that uses the same text - English translation by J.M. Neale - and is  sung on the same occasion: "All Glory, Laud, and Honor." The video below was recorded at St. Bart's in Manhattan, on Palm Sunday 2011. It begins with the blessing of the palms; the choir then sings Hosanna to the Son of David (I think this is Weelkes' setting) and the Gospel for this part of the liturgy is read.   The hymn itself begins after that, at around 8:45.



TPL says about this hymn that:

Composed by Theodulph of Orleans (d. 821), this hymn is often used as a processional hymn for Palm Sunday. According to a pretty little legend surrounding the composition of this hymn, Theodolf had been imprisoned for political reasons in a monastery in Angers. While he was imprisoned he wrote the hymn and sang it from the window of his cell just as Louis the Pious, King of France, was passing beneath the window in the procession on Palm Sunday in 821. The hymn so moved the king that he immediately ordered the holy bishop to be freed and restored to his see. The legend is now generally discredited on historical grounds. For a scriptural background of the hymn, see Matt. 21, 1-16 & Ps. 117, 26.

GLORIA, laus et honor tibi sit, Rex Christe, Redemptor: Cui puerile decus prompsit Hosanna pium. R. Gloria, laus, etc.	ALL glory, praise, and honor to Thee, Redeemer, King, to whom the lips of children made sweet Hosannas ring. R. All glory, etc.
Israel es tu Rex, Davidis et inclyta proles: Nomine qui in Domini, Rex benedicte, venis. R. Gloria, laus, etc.	Thou art the King of Israel, Thou David's royal Son, Who in the Lord's Name comest. the King and blessed One. R. All glory, etc.
Coetus in excelsis te laudat caelicus omnis, Et mortalis homo, et cuncta creata simul. R. Gloria, laus, etc.	The company of Angels are praislng Thee on high, and mortal men and all things created make reply. All glory, etc
Plebs Hebraea tibi cum palmis obvia venit: Cum prece, voto, hymnis, adsumus ecce tibi. R. Gloria, laus, etc.	The people of the Hebrews with palms before Thee went; our pralse and prayer and anthems before Thee we present. R. All glory, etc.
Hi tibi passuro solvebant munia laudis: Nos tibi regnanti pangimus ecce melos R. Gloria, laus, etc.	To Thee before Thy Passion they sang their hymns of praise; to Thee now high exalted our melody we raise. R. All glory, etc.
Hi placuere tibi, placeat devotio nostra: Rex bone, Rex clemens, cui bona cuncta placent. R. Gloria, laus, etc.	Thou didst accept their praises, accept the prayers we bring, Who in all good delightest, Thou good and gracious King. R. All glory, etc.

---

From the Roman Missal. Translation by J. M. Neale (1818-1866).

New Advent adds a bit more information:

Gloria, Laus et honor

A hymn composed by St. Theodulph of Orléans in 810, in Latin elegiacs, of which the Roman Missal takes the first six for the hymn following the procession on Palm Sunday (the use to which the hymn was always dedicated). The first couplet,

Gloria, laus et honor tibi sit Rex Christe, Redemptor,
Cui puerile decus prompsit hosanna pium,

is sung by chanters inside of the church (the door having been closed), and is repeated by the processional chorus outside of the church. The chanters then sing the second couplet, the chorus responding with the refrain of the first couplet, and so on for the remaining couplets until the subdeacon strikes the door with the staff of the cross, whereupon the door is opened, the hymn ceases, and the procession enters the church. The words of the refrain ("puerile decus") suggested the assignment of the hymn in the Middle Ages to boy chanters (thus at Salisbury, York, Hereford, Rouen, etc.). The hymn is founded on Psalm 23:7-10 (Vulgate); Psalm 117:26; Matthew 21:1-16; Luke 19:37-38.

Also from New Advent comes this bit of history, and a description of the Palm Sunday rite:

In the three oldest Roman Sacramentaries no mention is found of either the benediction of the palms or the procession. The earliest notice is in the "Gregorianum" used in France in the ninth and tenth centuries. In it is found among the prayers of the day one that pronounces a blessing on the bearers of the palms but not on the palms. The name Dominica in palmis, De passione Domini occurs in the "Gelasianum", but only as a superscription and Probst ("Sacramentarien und Ordines", Münster, 1892, 202) is probably correct in suspecting the first part to be an addition, and the De passione Domini the original inscription. It seems certain that the bearing of palms during services was the earlier practice, then came the procession, and later the benediction of the palms.

The principal ceremonies of the day are the benediction of the palms, the procession, the Mass, and during it the singing of the Passion. The blessing of the palms follows a ritual similar to that of Mass. On the altar branches of palms are placed between the candlesticks instead of flowers ordinarily used. The palms to be blessed are on a table at the Epistle side or in cathedral churches between the throne and the altar. The bishop performs the ceremony from the throne, the priest at the Epistle side of the altar. An antiphon "Hosanna to the Son of David" is followed by a prayer. The Epistle is read from Exodus 15:27-16:7, narrating the murmuring of the children of Israel in the desert of Sin, and sighing for the fleshpots of Egypt, and gives the promise of the manna to be sent as food from heaven. The Gradual contains the prophetic words uttered by the high-priest Caiphas, "That it was expedient that one man should die for the people"; and another the prayer of Christ in the Garden of Olives that the chalice might pass; also his admonition to the disciples to watch and pray. The Gospel, taken from St. Matthew, xvi, 1-9, describes the triumphant entry of Christ into Jerusalem when the populace cut boughs from the trees and strewed them as He passed, crying, Hosanna to the Son of David; blessed is he that cometh in the name of the Lord. (In private Masses this Gospel is read at the end of Mass instead of that of St. John.) Then follow an oration, a preface, the Sanctus, and Benedictus.

In the five prayers which are then said the bishop or priest asks God to bless the branches of palm or olive, that they may be a protection to all places into which they may be brought, that the right hand of God may expel all adversity, bless and protect all who dwell in them, who have been redeemed by our Lord Jesus Christ. The prayers make reference to the dove bringing back the olive branch to Noah's ark and to the multitude greeting Our Lord; they say that the branches of palms signify victory over the prince of death and the olive the advent of spiritual unction through Christ. The officiating clergyman sprinkles the palms with holy water, incenses them, and, after another prayer, distributes them. During the distribution the choir sings the "Pueri Hebræorum". The Hebrew children spread their garments in the way and cried out saying, "Hosanna to the Son of David; Blessed is he that cometh in the name of the Lord." Then follows the procession, of the clergy and of the people, carrying the blessed palms, the choir in the mean time singing the antiphons "Cum appropinquaret", "Cum audisset", and others. All march out of the church. On the return of the procession two or four chanters enter the church, close the door and sing the hymn "Gloria, laus", which is repeated by those outside. At the end of the hymn the subdeacon knocks at the door with the staff of the cross, the door is opened, and all enter singing "Ingrediente Domino". Mass is celebrated, the principal feature of which is the singing of the Passion according to St. Matthew, during which all hold the palms in their hands.

And in case you were curious, the Wikipedia page for "Latin elegiacs" says:

Elegiac refers either generally to compositions that are like elegies or specifically to Greek and Latin poetry composed in elegiac couplets, in which a line of dactylic hexameter is followed by a line of dactylic pentameter. Because the hexameter line is in the same meter as epic poetry and because the elegiac form was always considered lower style than epic, elegists frequently wrote with epic in mind and positioned themselves in relation to epic.

Classical poets
The first examples of elegiac poetry in writing come from classical Greece. The form dates back nearly as early as epic, with such authors as Archilocus and Simonides of Ceos from early in the history of Greece. The first great elegiac poet of the Hellenistic period was Philitas of Cos: Augustan poets identified his name with great elegiac writing.^[1] One of the most influential elegiac writers was Philitas' rival Callimachus, who had an enormous impact on Roman poets, both elegists and non-elegists alike. He promulgated the idea that elegy, shorter and more compact than epic, could be even more beautiful and worthy of appreciation. Propertius linked him to his rival with the following well-known couplet:

Callimachi Manes et Coi sacra Philetae,
 in vestrum, quaeso, me sinite ire nemus.^[2]

Callimachus' spirit, and shrine of Philitas of Cos,
 let me enter your sacred grove, I beseech you.

The 1st century AD rhetorician Quintilian ranked Philitas second only to Callimachus among the elegiac poets.^[3]
The foremost elegiac writers of the Roman era were Catullus, Propertius, Tibullus, and Ovid. Catullus, a generation earlier than the other three, influenced his younger counterparts greatly. They all, particularly Propertius, drew influence from Callimachus, and they also clearly read each other and responded to each other's works. Notably, Catullus and Ovid wrote in non-elegiac meters as well, but Propertius and Tibullus did not.

English poets

The "elegy" was originally a classical form with few English examples. However, in 1751, Thomas Gray wrote "Elegy Written in a Country Churchyard". That poem inspired numerous imitators, and soon both the revived Pindaric ode and "elegy" were commonplace. Gray used the term "elegy" for a poem of solitude and mourning, and not just for funereal (eulogy) verse. He also freed the elegy from the classical elegiac meter.
Afterward, Samuel Taylor Coleridge argued that the elegiac is the form "most natural to the reflective mind" and that it may be upon any subject, so long as it reflects on the poet himself. Coleridge was quite aware of the fact that his definition conflated the elegiac with the lyric, but he was emphasizing the recollected and reflective nature of the lyric he favored and referring to the sort of elegy that had been popularized by Gray. Similarly, William Wordsworth had said that poetry should come from "emotions recollected in tranquility" (Preface to Lyrical Ballads, emphasis added). After the Romantics, "elegiac" slowly returned to its narrower meaning of verse composed in memory of the dead.
In other examples of poetry such as Alfred Tennyson's "The Lady of Shalott" an elegiac tone can be used, where the author is praising someone in a sombre tone. J. R. R. Tolkien in his essay, 'Beowulf: the Monsters and the Critics' argues that Beowulf is a heroic elegy.