« REGINA CAELI ». – A major antiphon with which the Church greets and prays to the Blessed Virgin, associating her with the triumph of the Resurrection, through which she has become Queen of Heaven and universal intercessor. The *R. c.* is recited at the end of the Divine Office during Eastertide (from Compline of Holy Saturday to None on the Saturday after Pentecost). Its author is unknown, but it is attributed to Pope Gregory V (10th century).
It consists of four lines in accentual rhythm, the first two with a rhyming couplet (a, a) and the main tonic accent on the 1st, 4th, and 7th syllables (the *quia* of the second line is to be considered as anacrusis or introductory phrase), the third equivalent to two coupled quaternaries with assonance (*exit, exit*); the fourth, a seven-syllable line with the accent on the 1st and 6th syllables, stands apart. In this way, the *Alleluia*, at the end of each line, is considered a refrain that serves to fuse the brief poem into a single rhyme.
In antiquity it was used as a processional antiphon; then as a Paschal antiphon to the Gospel canticles (Benedictus and Magnificat), a use retained in the Votive Office of St. Mary on Saturday; then as a Marian antiphon at the end of the Divine Office, first (according to the testimony of John of Parma, 1249) among the Franciscans, and then, in 1350 (at Avignon, under Clement VI), in the Roman Curia Breviary. The current usage was regulated by the reform of Pius V (1568). As an antiphon to the Magnificat of Easter Octave, the *R. c.* is found in the Antiphonary of St. Peter (12th century), edited by I. M. Tommasi (Opera omnia, ed. A. F. Vezzosi, IV, Rome 1749, p. 100). With a trope (as a commentary) it appears in the Antiphonary of the convent of Rivoli, in use until the French Revolution (cf. S. Bäumer, Hist. du Brév., I, Paris 1905, pp. 422 ff.), and in cod. 314 of the monastery of Engelberg (fol. 74; cf. K. Young, The Drama of the medieval Church, I, Oxford 1933, p. 662).
The original Gregorian melody, from the 10th century, is in the 1st tone, less ornate but devotional; the one in use, in the 6th tone, simple and solemn, tender and joyful, dates from the 13th century; in its simplified form, from the 17th century. According to legend (Durandus, Ration. div. off., VI, 89, 3), the *R. c.* would have been sung by three angelic voices while an angel on high of the Mole Adriana sheathed the bloodied sword at the end of the sevenfold litany ordered by St. Gregory the Great for the liberation of the Roman people from the plague (cf. Divina Commedia, Par., XXIII, 127-129). Benedict XIV ordered that the *R. c.* Angelus (v.) during Eastertide (20 April 1742; cf. AAS, 25 [1933], pp. 71 ff.).