In 1560 the Confraternita del Santissimo Sacramento, i.e. the Brotherhood of the Most Holy
Sacrament, was instituted in the church of Santi Celso e Giuliano. The Confraternita primarily dedicated itself to bring the
Eucharist to the sick and indisposed. Apparently the building of the Oratorio di San Celso took place in 1591. In 1725 the cardinal
Nicolà Coscia, influential patron of the Confraternita, had the oratory restored. Further restorations occurred in 1878 and after
an earthquake in 1915. The oratory remained the seat of the Confraternita del Santissimo Sacramento until 1984, when
the Confraternita was transferred to its new premises. After this the oratory was handed over to the charity organization
Caritas Diocesiana di Roma as a meeting-place. Although since 1993 the oratory has been in a state of abandon.
The façade, restored in the 1990s, has two storeys, of which the lower has four Ionic pilasters resting
on high socles. On both sides of the entrance portal there are lateral niches decorated with sea-shells. The upper storey has
a small window in the middle and volutes on the sides. The small interior shows obvious signs of disrepair. The high-altar
painting, Christ and Saint Peter at the Last Supper (1725, probably a copy of a late 16th century original), has been
lost and is now replaced with a wooden Crucifix. Above it the Divine Triangle with golden rays of light can be seen. The fresco
of the vault (18th century), partly ruined, depicts the Assumption.
Oratorio di San Celso is situated in Vicolo di San Celso between Via
dei Banchi and Via di Panico among the many streets and alleys in the rione Ponte, i.e. Ponte region. Sometimes the oratory (small
prayer chapel) is referred to as San Celsino (Italian diminutive of San Celso) to distinguish it from the church of Santi Celso e
Giuliano in Via del Banco di Santo Spirito nearby. The oratory is dedicated to Saint Celsus, martyred at Antioch in 302 A.D.