OSTENSORIO. – It is a sacred vessel (monstrantia, tabernaculum [mobile or portable], custodia) used for the solemn exposition of the Most Holy Sacrament and for carrying it in procession, employed only in the Latin Church.
It consists of a kind of reliquary (square, round, or cylindrical in shape) fitted with glass, supported by a foot similar to that of a chalice. The Host is placed in a semi-circular support (called a lunula or lunetta because of its half-moon shape, sometimes referred to in southern Germany as «Melchisedech»; Gen. 14:18), fixed in the reliquary by means of a groove. The whole, varying in height from 40 to 120 cm., is surmounted by a small cross (S. Congr. of Rites, decree 2957). Neither the material (gold, silver, gilded copper; decree 3162 ad 6) nor the blessing is prescribed; only the lunetta, for convenience made of gilded metal, is blessed (decree 926 ad 5).
The ostensory was introduced in the 14th century following the more common practice, in the 15th century, of exposing the Most Holy Sacrament for public adoration. At first, the exposition was made with a pyx or a box-like vessel fitted with glass.
A. R. – In the Gothic period (14th–15th centuries), when its use spread alongside that of reliquaries, of which it is a derivation, the ostensory was designed as a small temple, the house of the Lord, and, closely adhering to architectural models, it featured spires, pinnacles, buttresses, and statuettes, varying according to regional styles. In Venice, crystal predominated; in Sicily and Sardinia, there were reflected arches in the Catalan style; in Lombardy, the forms were more rigid and iron-like (examples in Lovere, church of S. Giorgio; Rossano, Cathedral; Milan, Sforza Castle, etc.). Following the example of the grand ostensories made in Spain and southern Italy, particularly in Sicily, some reached a height of about 2 meters and had to be carried on the shoulders during processions.
An exceptional example is the one preserved in the cathedral of Enna, a work by Paolo Gili (16th century). During the Renaissance, in various regions, goldsmiths drew inspiration from the new architectural styles for the forms of ostensories; thus, the general shape remained unchanged, but colonnettes, pediments, and small domes replaced buttresses and spires, seeking greater harmony in proportions and decorating the base and shaft with fine engravings (Peja, church of S. Antonio; Corlago, church of S. Pancrazio, etc.).
From the 15th century onward, another type of ostensory, known as the «sun» type, became preferred. Identifying the Eucharist with the radiant sun, the glass reliquary containing it was enclosed by a circular frame from which rays of varying length extended, often alternating in gold and silver, adorned with gems or enamel flowers (Palermo, S. Domenico) or corals (Trapani, National Museum). The inventiveness of artists gave this type other decorative features: the shaft was interrupted or formed by figures of saints supporting the sphere (Padua, church of S. Luca; Castel di Sangro, Cathedral), or by pairs of angels (Bagnara, parish church; Stilo, church of S. Giovanni Teresti; Vibo Valentia, church of S. Leo Luca, etc.). Freed from any architectural constraints, in the 18th century the ostensory assumed splendid forms in perfect unity of movement, rising from the base to the shaft in a whirl of gold, culminating in the radiant sphere crowned by adorant angels, or covered with clusters of grapes and ears of wheat, as favored by goldsmiths such as Filiberto, Michele Kuerner of Vienna, Angelo Spinazzi, Mercurio, Sebastiano Juvara, and many others (e.g., Chiuduno [Bergamo], church of Maria Assunta; Bergamo, church of S. Alessandro della Croce; Piacenza, church of S. Lazzaro; Palermo, National Museum; Messina, church of Monte Vergine, etc.).
The neoclassical taste at the beginning of the 19th century stiffened the forms but did not substantially alter the type, which remained the preferred model for industrial reproductions. More recently, at various exhibitions of sacred art, it has been seen how insistently, and often with refined techniques, modern goldsmiths have developed the motif of the ostensory, frequently achieving the same nobility as the ancient models. – See pl. XXIX.