San Salvatore in Onda is a restored 13th century convent church at Via dei Pettinari 51 in the rione Regola. Pictures of the church at Wikimedia Commons are here. There is an English Wikipedia article here.
The dedication is to Jesus Christ our Saviour.
This was possibly one of the many parish churches founded in the built-up area in the 10th and early 11th centuries. As with almost all of the others, nothing has been documented concerning its foundation.
The first mention dates from 1127, when the church is referred to as Salvatoris in Unda. Then it is listed in 1186 as one of the parish churches dependent on San Lorenzo in Damaso.
The extant crypt dates to about the earlier year, and so the church was built or rebuilt about then.
The Latin word unda literally means "wave of the sea", but metaphorically could also mean a flood. So, it is fairly secure that the appellation of the church refers to the flooding of the Tiber, which caused severe problems in Rome until the embankments were built in the late 19th century. During floods, the water would invade the houses in the area (if the flood was serious, the river would simply take a short-cut across its meander and you could row a boat to the Spanish Steps).
The church was rebuilt (except for the crypt) in 1260 by one Cesario Cesarini, and this is structurally the present building.
Towards the end of the century a little convent attached to the church became the first Roman headquarters for the Order of St Paul or the Paulines, a monastic order which took its inspiration from St Paul the First Hermit and which became popular in eastern Europe. This received its definitive approbation from the Holy See in 1308.
However, by 1435 the Paulines had moved out. In 1454 they were persuaded by Pope Nicholas V to take over the church of Santo Stefano Rotondo al Celio after that pontiff had overseen a restoration there. They eventually settled at San Paolo Primo Eremita.
The parish was kept up, although it was small even compared to other nearby in this over-churched area. A 1566 visitation noted only about forty households, and the parish would probably have been suppressed if the friars hadn't been there.
In 1684, there was a major restoration in the Baroque style. The arcade colums were encased in piers, and this is why Faustino Corsi in his monumental listing of ancient columns in the city in 1833, Delle Pietre Antiche, does not list the ones here now. Also, the original Gothic pointed windows in the nave side walls were rounded off.
The complex was vacated by the Franciscans in the early 19th century, which doomed the parish. A major re-ordering of the parishes of the Centro Storico took place in 1824, under the bull Super Universam issued by Pope Leo XII. This suppressed the parish attached to the church.
The latter was saved by St Vincent Pallotti. The "Second St Philip Neri" was a native Roman priest who had founded the Society of the Catholic Apostolate (Pallottines) in 1835, and he was granted the complex here to be its headquarters in 1846.
A major restoration of the church was undertaken from 1867 to 1878 by Luca Carimini. This involved returning the Baroque interior to what he thought the mediaeval church looked like -actually more accurate than the "restorations" that afflicted some Roman churches later on, as the mediaeval people actually preferred colourful frescoes to bare brick and plaster.
The Pallottines have been here ever since, and their apostolic outreach is highly regarded. In 1950 their founder was beatified, and in 1963 he was canonized. His body is now enshrined under the high altar.
Layout and fabric
The church is basilical in plan, and has a central nave of seven bays with side aisles. There is a large external chapel off the right hand side aisle, and an external semi-circular apse slightly narrower than the central nave.
Because of the surrounding conventual buildings, only the façade is visible from the narrow street.
The façade is a very straightforward 19th century design, rendered in pale yellow with architectural details in white and a dado painted in grey.
There are three vertical zones, the central one being wider. This central zone is flanked by a pair of
Doric pilasters in shallow relief, supporting an entablature which is run over the two side zones but without any corner pilasters. Above and between the pilasters this entablature has a plain architrave, a frieze decorated with triglyphs and dentillations under the cornice, but over the side zones there is no architrave and the frieze and cornice are plain. Over the decorated part of the entablature is a triangular pediment.
The single doorway has a molded doorcase, and a raised horizontal cornice supported on volute brackets. Over this is a large sunken rectangular panel, which looks as if it was intended for a fresco. Over that in turn is a string course bearing a short dedicatory epigraph Christo Salvatori; this string course is continued across the entire façade behind the pilasters. On the central section of the string course is a large lunette window with a molded archivolt which touches the architrave of the crowning entablature.
The side zones each have two rectangular windows, above and below the string course.
The fabric of the church is substantially mediaeval, but the main body of the interior is 19th century in appearance. The church has a very interesting mediaeval crypt, however. There is a nave of seven bays, with side aisles. At the ends of the aisles are two chapels, and a third large chapel is off the right hand side aisle. There is no structural transept or sanctuary apart from the semi-circular apse.
The single entrance leads into a very shallow entrance lobby, with three interior doors within a counterfaçade arcade of three arches on Doric pilasters. This supports a gallery, with a solid balustrade in a polychrome chequerboard design over an entablature with a frieze bearing the epigraph Laudate Dominum in tympano et choro, chordis et organo ("Praise the Lord with tambourine and choir, strings and organ"), a quotation from Psalm 150. Above the gallery is the large lunette window to be seen in the façade. Unusually, the organ is built on two floating corner platforms on either side of this.
The nave arcades rest on ancient columns, which have Corinthian and composite capitals with thin imposts from which the arcade archivolts spring. Eleven of the capitals are ancient, but one is mediaeval. The twelve columns are from various ancient buildings, and are not a matching set. Four are of grey granite, three of white marble, two of bigio lumachellato which is a grey marble, one of greco fasciato which is white with grey veins, one of cipollino which is white with green smears and one of pavonazzetto which is white with purple veins. Some are ribbed. These were high-status items originally.
Above the arches is an entablature with a strongly projecting and dentillate cornice, which runs around the church, and does not touch the archivolts. The zone between archivolts and entablature is embellished with swags and angels, and the intradoses of the archivolts have what amount to pot plants. The frieze of the entablature displays a very odd collection of Christian symbols.
Above the entablature, the nave side walls have round-headed windows interspersed with round-headed frescoes of the same size. They are separated by composite pilasters bearing grotesque decoration, and the walls around are in red with a geometric pattern. There are eight in total of the frescoes, depicting Old Testament characters. From the bottom right, they are: David, Samson, Joseph, Noah, Isaac (about to be sacrificed), Aaron, Joshua and Ezechiel (holding a plan of the Temple of which he had a vision).
The central nave roof is flat, in wood with coffers arranged in square groups of four squares each, with rosettes on a red background. These are separated by cross-shaped panels in blue and gold. The side aisles are cross-vaulted, in blue.
The sanctuary area occupies the apse and the last bay of the central nave, which is sequestered by a low balustrade. The apse has a triumphal arch with a molded archivolt enclosing the conch and flanked by a pair of angels in the spandrels. Its ends are supported by a pair of ribbed Corinthian piers.
The high altar has the relics of St Vincent Pallotti displayed like a mannequin in a glass case beneath it -when he was exhumed in 1950 his body was incorrupt, so those are his real face and hands. This altar has a baldacchino with four Corinthian columns in red and white marble, supporting a canopy of four arches over which is an entablature with a frieze in red. There is a triangular pediment on each side. The internal cupola has integrated pediments, and its decoration is worth looking at. The Dove of the Holy Spirit in relief is in the middle, surrounded by a ring of eight tondi containing reliefs of apostles, while the pendentives have reliefs of the Evangelists in small pedimented niches.
The apse displays frescoes of SS Peter and Paul, either side of an icon of the Madonna and Child in its own neo-Classical aedicule with a pair of ribbed Corinthian columns and triangular pediment. This is corbelled out over a tabernacle of a good design, with polychrome marble work around a silver-gilt relief of the Pelican in Piety on the door (the myth was that the pelican fed its chicks on its own blood).
The icon itself is by Cesare Mariani, and is dated 1878.
The conch of the apse depicts The Transfiguration, with Christ in glory accompanied by Moses and Elijah.
Cappella Virgo Potens
Off the right hand aisle is a side chapel dedicated to the Blessed Virgin Mary under her title of Virgo Potens ("Powerful Virgin"). It is semi-circular, with a semi-dome coffered in squares with gilded rosettes on blue. The entrance piers are in white, with gilded relief highlights showing grotesque motifs.
The altar is in polychrome marbles, with a pair of grey-veined cream-coloured composite columns supporting a horizontal architrave with its frieze in verde antico. The altarpiece is a fragment of a painting showing the Madonna and Child, set in a tondo.
The aedicule is flanked by four large frescoes by Mariani, separated by composite pilasters in what looks like porphyry and purple-veined marble. The subjects are: Judith with the Head of Holofernes, Queen Esther Before Ahasuerus, The Annunciation and The Immaculate Conception and St Anthony Appear to a Franciscan Friar (who?). These paintings are technically accomplished.
The icon was donated by the Venerable Elizabeth Sanna, a Franciscan tertiary nun whose memorial slab is in the floor in front of the altar.
Chapel of SS Cosmas and Damian
The chapel at the end of the right hand aisle displays an altarpiece showing SS Cosmas and Damian having a vision of Christ in glory.
Chapel of Our Lady of the Angels
The left hand aisle chapel has a sculptural relief of Our Lady of the Angels, being venerated by two saints (who?).
There is a small crypt of three bays with a cross-vaulted ceiling below the sanctuary. It was originally accessible via stairways from both sides of the sanctuary, so would seem to have been a focus of pilgrimage when it was built in about the early 12th century. If so, it is not known what was venerated here.
The vault is held up by two short ribbed Ionic columns, which are re-used ancient items. Further fragments of columns are embedded in the walls. The altar is made from a massive Corinthian capital.
The metal trap-door in the floor gives access to excavated early 2nd century remains of commercial premises.
Rooms of St Vincent
The rooms of St Vincent in the convent, where he lived from 1846 until his death in 1850, have been turned into a museum and contain many relics of him.
The church is advertised by the Diocese (June 2019) as being open from 8:00 to 12:00 daily.
Mass is celebrated, according to the same source:
Sundays 7:00, 11:00.
Only worshippers are allowed in the church during Mass.