(Translated from Lebrun’s Explanation and also published at Liturgical Arts Journal)
The chasuble, casula or planeta was a large round mantle with an opening at the top to pass the head through. During the first seven centuries, it was the ordinary long garment of men. The people stopped using it, but consecrated persons retained it. The Capitularies of 742 ordered priests and deacons not to stop wearing it; and for nine hundred years the Church has given the chasuble to priests at their ordination as the standard garment for offering the Holy Sacrifice. The Greeks have kept the chasuble without any modification, while in the last two centuries the Latins have cut it back little by little, removing that part that impeded the free movement of the arms. Previously it was necessary to roll and lift up the priest’s chasuble during the incensation and the elevation of the Sacred Host or chalice, something which is still done unnecessarily purely out of custom. The chasuble, as a garment that covers the whole body, has been seen as a fitting representation of Christ’s yoke, represented by the cross depicted on it either in front, as in Italy; or on the back, as in France; or both in front and back as has been done in Germany, in keeping with the pious sentiments of the author of the Imitation of Christ, for the last three hundred years. The priest who puts aside his own glory to carry the cross of Jesus Christ thus has a right to say as he puts on the chasuble: O Lord, Who said: My yoke is sweet, and My burden light: grant that I may be able so to bear it, that I may be able to obtain Thy grace.
Vestments particular to deacons: The Stole and Dalmatic
Besides the amice, alb, cincture and maniple we have mentioned, deacons wear also the dalmatic and a stole peculiar to themselves.
The stole of deacons was originally, as that of priests, a long, thin cloth attached to the left shoulder, something like how the principal Master of the Feast in the Romans’ solemn feasts wore an honorary serviette on his left shoulder, as one can see in the triumphs that Onuphre Panvin has described and had engraved.
This white cloth attached on the left shoulder of the deacons fluttered about as they came and went in the Church during their ministry. Saint John Chrysostom says that the two flowing and fluttering ends imitated the wings of angels, and represented their activity, as Simeon of Thessalonica also remarked after Chrysostom. Gregory of Tours, in the 6th century, still speaks of the orarium as a very white cloth. The Fourth Council of Toledo in 633 ordered deacons to wear only one orarium on the left shoulder, and forbade it to be decorated with gold or to be colored. But in many other Churches the enthusiasm for embellishing everything that was used in the holy mysteries was the reason they came to be decorated. In ancient times the Latins and also the Greeks wore the stole on the left shoulder and let it fall in front and behind, something like the orarium or white cloth that St. John Chrysostom described. We see these hanging stoles in many ancient depictions. But because these two long and flowing ends could encumber the deacon as he moved about, during the Communion the Greeks decided to remove it from the left shoulder and let it fall around the shoulders and chest, forming a cross in front and behind. The Latins, leaving it on the left shoulder, have been content to let the two ends fall and stop on the right side, so as not to be hindered by letting it flow. We observe this currently in practice, and some even, to keep it from fluttering entirely, it is placed under the dalmatic; though the ancient depictions and the Council of Braga show us that it was placed above.
The dalmatic, so-called because it came from the Greek province of Dalmatia, was introduced in Rome in the second century. It was an ample tunic with large, short sleeves, suitable for those who were obliged to move about. The garment thus became very useful and common among bishops and deacons. In the Acts of the martyrdom of St. Cyprian, we can see that this saint left his mantle to his executioners and gave his dalmatic to the deacons.
The deacon Hilary, authors of the questions on the Old and New Testaments which he wrote about three hundred years after the conquest of Jerusalem, or around 365, says that the deacons and the bishops both wore the dalmatic. St. Isidore, in the 6th century, regards the dalmatic as a sacred garment, white, and decorated with purple bands. Remigius of Auxerre describes it as a white garment with red bands. This is how the deacons’ dalmatic became a garment of solemnity that was meant to inspire holy joy, in the expression of the Pontifical.
In Lent, and in certain other days of penitence in which vestments of joy are not suitable, the deacons wear the chasuble, which in the earliest times was the most common garment of the clergy. But in order to move about without being hindered, before beginning the Gospel they take off the chasuble, fold and twist it, and place it on the left shoulder, and let it fall behind along with the stole under the right arm, where it is held by the cincture.This is what Amalarius in the 9th century and the pseudo-Alcuin give us to understand. The deacons still wore the stole hanging from the left shoulder. Thus, when they let one of the ends fall in front and the other behind, and fixed them on the right side as is the current practice, they also adjusted the folded and twisted chasuble in the manner of a sash over the stole. But later, in place of the folded chasuble and the sash-arrangement, a band of fabric was substituted. The Roman, Parisian, and other missals call this the stola latior. In certain churches, as at Cambrai, Arras, etc., in order to better approximate the folded and twisted chasuble, they place a band of stuffed fabric over the ordinary stole.
While the deacons do not take off the chasuble, they fold it, not from each side toward the right and left shoulders, as priests once did, but only in front, in order to grant their arms some freedom of movement. Indeed the chasubles are so trimmed in this way that it is no longer necessary to raise them; but it serves nevertheless to recall the spirit of the ancient custom, and to distinguish the chasubles of the ministers from that of the priest.
 Casa means house, and casula a small house. The chasuble was formerly so ample that it was like a small house in which a man lived. Planeta means something that wanders. The chasuble which has only one opening to pass the head through and which was formerly a round and completely unadorned mantle, without any special feature to distinguish front from back, could be rotated easily about the neck. Thus it was a “wandering” vestment very suitably named “planet.”
 Several of these great chasubles are still kept at Notre-Dame of Paris, Saint-Denis, Saint-Martin-des-Champs, and at the Chartreux. Priests who are not ashamed to wear this cumbersome garment still use them from time to time. Some of these great chasubles had a cap attached, as can be observed in several ancient depictions, but there are few examples of these and the ancient books speak nothing of them. At the Cathedral of Metz they are put to use during Advent and Lent; and only on ferial days during Lent at the Collegiate Church of Saint-Sauveur. They are employed at Narbonne, Toul, Cambrai, and Arras; and on Holy Thursday at Paris.
 Decrevimus quoque ut presbyteri vel diaconi non sagis, laicorum more, sed casulis utantur ritu servorum Dei (Conc. vol. 6 col. 1535; Capitul. vol. 1, pg. 148).
 See the Sacramentary of Senlis written in 880 and kept in Paris at the Library of Sainte-Geneviève: Presbyteris quando vestitur casula: Benedictio Patris, et Filii, et Spiritus sancti descendat super te, et sis benedictus in ordine sacerdotali, et offeras placabiles hostias pro peccatis, etc. This prayer Benedictio is also found in the Missal of Saint Eloi, Sacram. de S. Greg. p. 238. It also appears in the Pontifical of Seez, of 1045: Recipe planetam ut possis legaliter celebrare Missam (Bibl. Reg. n. 3866).
 Book 4, chapter 5.
 Domine, qui dixisti, jugum meum suave est, et onus meum leve, fac ut istud portare sic valeam, quod consequar tuam gratiam.
 In the Catalogue of the ancient popes, written at the beginning of the reign of Justinian, we find this Constitution of Pope Zosimus: Constituit ut diaconi laevam tectam haberent de palliis linostinis. See the Propylaeum Maii, pg. 53, of the learned Jesuits of Anvers, who continue to publish the Acts of the saints.
 De Triumphis [Ed.: Or rather, perhaps, his De Ludis Circensibus (1600)]
 Hom. de filio prodigo. (Pseudo-Chrysostom, PG 59 520 ln. 1-3): “Dum ministri sacri officii, imitantes angelorum alas tenuibus suis lineis velis, quae sinistris humeris insident […].}
 Simeon Thess. de Templo: [Or rather De clericis ordinandis, PG 155, 382-383, ch. 173-174]: “Ille enim orario velut aliis conspicuus fit et splendidus….Sed praesertim dum communionis fit particeps Seraphim illa imitatur […]. Ideo diaconus ut Seraphim figurantibus flabellum a pontifice traditur. Illa autem alas angelorum designat […]. Angelorum autem ordinem et vices sustinent […]. ”
 This stole, long called an orarium, was a sign of the deacons’ jurisdiction, since they used them in the church to make announcements, to read, to pray, or to order a genuflection, as in the Jewish synagogues someone held a kerchief in his hand to invite the people to say Amen. See Casaubon and Fr. Morin. This is why the Council of Laodicea forbade subdeacons from wearing this orarium. (Can. 22). And when during the ordination the deacons are given the power to read the Gospel in the church, this orarium is also given as a mark of this power: Recipe istud orarium, ut habeas licentiam legendi Evangelium (Pontif. Sagiense ms. sec. XI from the Royal Library).
 Orarium candor lintei, etc. (De gloria Mart. vol. 2, chapter 93. 105.
 Unum orarium oportet Levitam gestare in sinistro humero…Caveant ergo Levitae gemino uti orario, sed uno tantum et puro, nec ullis coloribus aut auro ornato (Conc. Tolet. c. 39).
 Though the deacon’s stole was worn anciently on the left shoulder, they have worn it around the neck in various times in many French churches, the two ends hanging in front like that of bishops and priests. This is discernible in many depictions: in that of St. Vincent the Deacon, on the portal of St. Germain-l’Auxerrois de Paris; in that of Saint Etienne, on the portal of the Cathedral of Metz [Ed.: Does not appear today]; and again we find it in Amalarius, Deacon of Metz, who says with regard to the deacon’s stole that it descends to the knees, stola ad genua tendit, and that he wears it around the neck, sciat se diaconus in stola superposita collo (Ministrum, etc., book 2, chapter 20). But when Amalarius had been to Rome, he saw that before the Gospel the deacon put aside the chasuble, rolled it, and let it pass behind with the stole under the right arm, so that until the Gospel a part of the stole hung in the back. This is what he tells us in his additions: Stolamque post tergum ducit subtus dextram alam una cum planeta (Praefat. 2 in lib. de Offic.). Later this practice of putting the stole over the left shoulder was adopted everywhere. In the 13th century, Durandus supposed this practice had been perennial, that the deacons had always worn it that way, and he only gave the reason why: Cur sacerdotibus circa collum, et diaconis super sinistrum humerum ponatur (Book 3, chapter 5). The new Pontifical, like the ancient ones, takes it for granted in the ordination of priests, when it says that the bishop takes the stole from the left shoulder to pass it over the right, and adjusters the part of the stole that hangs in back to place it over the chest: Reflectit orarium, sive stolam ab humero sinistro cuiuslibet, capiens partem quae retro pendet, et imponens super dexterum humerum aptat eam ante pectus.
 In the Glossaire Latin and Glossaire Grec of M. du Cange.
 Vide Euchol. Graec. pg. 147.
 Quia in aliquantis huius Provinciae Ecclesiis diacones absconsis infra tunicam utuntur orariis, ita ut nihil differre a subdiacono videantur, de caetero superposito scapulae (sicut decet) utantur orario (Con. Brac. I, (561), c. 8).
 Isid. orig. Book 19, chapter 22.
 See Lamprid. Hist. Aug.
 Et cum se dalmatica exspoliasset, et diaconibus tradidisset, in linea stetit (Cypr. act.).
 Quasi non hodie diaconi dalmaticis induantur sicut episcopi (Quaest. 46 apud Aug. vol. 3 append. col. 60).
 Dalmatica… tunica sacerdotalis, candida cum clavis ex purpura (Isid. orig. Book 19, chapter 22).
 Eadem vestis (dalmatica) candidatem habet… et coccineas virgulas (Rem. Aut. Expos. Miss.).
 Induat te indumento salutis, et vestimento laetitiae (De ord. diac.).
 See the Roman Ordo’s of the 14th and 15th centuries: Complicent et imponant super sinistrum humerum… ita quod ab humero sinistro descendat ad latus dextrum, sicut diaconalis stola (Ord. Rom. XIV). Exuit planetam, et plicatur ei ad modum stolae… ad latus dextrum inter cinctorum (Ord. Rom. XV). See also Gavantus in Rubr. p. 1, tit. 19, n. 6; M. Bocquillot and M. de Vert.
 Exuit se planeta diaconus, stolamque post tergum ducit subtus, dexteram alam una cum planeta (Amalarius, praefatio in lib. de offic.)
 Diaconus qui non est indutus dalmatica, casula circumcinctus legit (Alcuin de divin. offic.).
 Planeta…. complicatur: aut enim aliud genus stolae latioris in modum planetae plicatur (Rub. Miss.).