Agnus Dei (Lat. Lamb of God).
I. A hymn generally supposed to have been introduced into the Roman Mass service by Pope Sergius I in 688. It is more probable that before his time it had been sung by the clergy alone, and he only required the laity to join. The hymn is founded on Joh 1:29, begins with the words Agnus Dei, and is sung at the close of the mass. For a full account of the hymn and its varieties, see Pascal, Liturg. Cathol. p. 51.
II. A cake of wax used in the Romish Church, stamped with the figure of a lamb supporting the banner of the cross. These cakes, being consecrated by the pope on the Tuesday after Easter in the first and seventh years of his pontificate, are supposed by Romanists to possess great virtues. They cover them with a piece of stuff cut in the form of a heart, and carry them very devoutly in their processions. From selling these Agni Dei to some, and presenting them to others, the Romish clergy and religious officers derive considerable pecuniary advantage. The practice of blessing the Agnus Dei took its rise about the 7th or 8th, according to others, about the 14th century. Though the efficacy of an Agnus Dei has not been declared by Romish Councils, the belief in its virtues has been strongly and universally established in the Church of Rome. Pope Urban V sent to John Palaeologus, emperor of the Greeks, an Agnus folded in fine paper, on which were written verses explaining all its properties. These verses declare that the Agnus is formed of balm and wax mixed with chrism, and that being consecrated by mystical words, it possesses the power of removing thunder and dispersing storms, of giving to women with child an easy delivery, of preventing shipwreck, taking away sin, repelling the devil, increasing riches, and of securing against fire. SEE LAMB.
III. It also signifies, like the Greek word Poteriocalymma (ποτηριο- κάλυμμα), a cloth embroidered with the figure of a lamb, with which, in the Greek Church, the cup at the Lord's Supper is covered.
See generally Fabricius, Bibliog. Antiquar. ed. Schaffhausen, p. 522; Pope Sixtus V, Breve de more benedicendi et consecrandi ceream quae Agnus Dei vocatur, in the Giornale de' Letterati d'Italia, 17, 435; Heine, Dissertt. Sacrar. (Amst. 1736), 1. 2, c. 12; Munter, Sinnbilder d. ersten Christen, 1, 80 sq.; Gerbert, De canto et musica sacra, 1, 454 sq.