Vexilla Regis

In 569 the Byzantine emperor Justin II sent a relic of the True Cross to Radegund, the Thuringian princess who had left her Frankish royal marriage to found the monastery of the Holy Cross at Poitiers. For its solemn reception on 19 November of that year, the Italian poet Venantius Fortunatus, then living at Poitiers, composed Vexilla regis prodeunt, the banners of the king go forward, and the hymn's first audience watched an actual procession, relic, clergy and royal foundress, as it was sung.

Fortunatus imagined the cross as the vexillum, the Roman military standard, advancing before the King of heaven, and built the hymn on the paradoxes the cross had gathered in Christian imagination, the tree on which life himself died and by death brought forth life, the wood honoured to bear the ransom of the age and to weigh the price of the world.

One stanza quotes and corrects the psalter, God has reigned from the tree, an old Christian reading of Psalm 96. The address to the cross itself, O crux ave, spes unica, hail O cross, our only hope, became one of the most repeated lines in Latin Christianity, engraved on monuments and gravestones wherever the language reached, the whole hymn a case of court poetry, relic politics and theology fused into permanent liturgy.

The Roman office assigned Vexilla Regis to Vespers in Passiontide, the last two weeks of Lent, when the church's attention closes on the cross, and to the feasts of the Holy Cross, and it is sung on Good Friday as the reserved sacrament is carried to the altar, the banners of the king advancing at the rite's darkest hour. Its military imagery gave it a second, rougher history, the hymn of the standard was adopted as a crusading song, and vexilla regis passed into the vocabulary of Christian armies, a reminder that liturgical poetry does not control its own reception. Dante paid the hymn literature's strangest compliment.

The final canto of the Inferno opens Vexilla regis prodeunt inferni, the banners of the king of hell advance, announcing Satan by parodying the hymn every reader would know, the frozen counter procession at the bottom of the world. Composers have returned to the text steadily, in chant, in Renaissance polyphony, and notably in Bruckner's late motet, while Liszt built a movement of his Via Crucis on it, and the hymn's stanzas, lightly revised over the centuries and restored in modern books, remain in the Liturgy of the Hours, so that a processional written for one afternoon in sixth century Poitiers is still doing annual duty wherever the Latin rite keeps Passiontide.