Santi Venanzio ed Ansovino was a parish and regional church that used to stand on the east side of the Via di San Venanzio in the rione Campitelli, on the present open space north-east of the Fountain of Pope Sixtus V.
The first evidence for the existence of this church was a memorial epigraph transcribed by Bruzio, which read: Hic reequiescit [sic] Cola Alexi de Planellari, sub anno Dni MCCLXIIII, mense Augusti. This gives the year 1264, but the church was certainly older than that by at least a couple of centuries.
In the Middle Ages it was named San Giovanni in Mercatello after the market that used to be held "on" the Campodoglio, presumably at the foot of what is now the Cordonata. The dedication was to St John the Baptist. This market was the main one for the city, and remained here until 1477 when Pope Sixtus IV moved it to the Piazza Navona as part of the campaign to restore some glory to the Capitoline.
In 1543 the church was granted to the newly-founded College of Catechumens, which was the forerunner of the College of Neophytes attached to Santa Maria dei Monti. When the institution moved to the latter church in 1634, San Giovanni was given to the Byzantine-rite monks of Grottaferrata who had previously established a little monastery at what is now Santa Maria del Buon Consiglio ai Monti.
However, the monks were not here long because in 1665 the church was granted to a confederacy of expatriates from Camerino, which is now a small town of little importance in the Marches but then had more dignity as a walled city.
They restored the building in the Baroque style to a design by Antonio Liborio Raspantini, himself from Camerino, and changed the dedication to SS Venantius and Ansovinus. These are two saints of Camerino who do not belong together, since the former was a legendary martyr of the 3rd century who has been deleted from the Roman martyrology, and the latter a bishop of the city in the 9th century. So, the church had a double dedication rather than a joint one.
In the mid 19th century the confraternity was suppressed, and the church granted to the Pious Union of the Sacred Heart of Mary. At the end of the century it was famous as one of the more pastorally effective churches in the city, popular among ordinary people.
The church was demolished in 1928 as part of the Fascist ideological determination to provide Rome with a triumphal cityscape, which here involved surrounding the Vittorio Emanuele monument with open spaces rather than old buildings. Some artworks were transferred to the new church of Santi Fabiano e Venanzio a Villa Fiorelli, which was also made the regional church of Camerino.
The church was located on what is now the Via di San Venanzio, and the entrance was directly opposite that of the Palazzo Muti Bussi. The old street was fairly wide here, and the kerbstones on the east side of the present street are about where the line of the façade used to be. The Fascist had their triumph in replacing this Baroque church with grass.
The church was quite small, but had a rather unusual basilical plan. The nave had aisles, with arcades supported by two pillars on each side. The presbyterium was apsidal in form, with a semi-circular far end, but beyond this was the true apse which was square in plan. The aisles were extended parallel with this by long, narrow side chapels.
The two-storey façade had an entrance doorway flanked by pilasters with capitals and topped by a raised segmental pediment. There was a pair of tripletted Corinthian pilasters on either side, supporting the entablature dividing the storeys and which had an overhanging cornice. Above the door was an arched window, the arch having double pilasters with capitals. The second storey had four Ionic pilasters, the inner pair supporting a segmental pediment and the outer ones, a pair of urns. There was a central window in this storey as well, but this one had single pilasters and a triangular pediment.
The main altar was designed by Giovanni Battista Contini, and had an altarpiece of God the Father with Saints by Luigi Garzi. It was flanked by paintings by Agostino Masucci, and the vault above was frescoed by Pasqualini.
The left hand chapel had Our Lady with SS Charles Borromeo and Philip Neri by Garzi again. The dedication was to St Charles.
The right hand chapel was dedicated to Our Lady, and was designed by Antonio Gherardi, who executed the altarpiece showing Our Lady with St Anne. The vault fresco by Michelangelo Cerruti showed the Assumption, and he also executed the Nativity on one side wall. The other wall was frescoed by Giovanni Antonio Grecolini.