Santa Maria della Clemenza a Trastevere is a deconsecrated early 17th century oratory at Vicolo del Piede 14 in Trastevere.
The dedication was to the Blessed Virgin Mary, under her title of Our Lady of Mercy.
The oratory was founded in 1600 for a confraternity which prayed for the souls in Purgatory. This was itself founded in 1504 by one Giovanni Colli, and was the forerunner of the brotherhood at Santa Maria Addolorata in Trastevere.
However, in 1675 the oratory was granted to the Arciconfraternita del Santissimo Sacramento di Santa Maria in Trastervere, which was founded to propagate Eucharistic and Marian devotion. They provided a copy of the Byzantine icon of Our Lady of Mercy (Madonna della Clemenza) for veneration here, the original being in the Altemps Chapel at Santa Maria in Trastevere where they used to meet before moving here.
An alternative name for the oratory was Santissimo Sacramento a Trastevere.
It is now deconsecrated, and has been converted into a trattoria called La Canonica. (There used to be a website, but this is defunct.)
The edifice was a rectangular nave of three bays, with the side walls coved in between the pilasters supporting the ceiling vault. There was a separate tiny, shallow rectangular apse.
The planned façade never materialized. However, a dedicatory inscription can still be seen above the entrance door (obscured by an arbour of creepers). Also visible is some stucco relief decoration showing putti pulling back a curtain.
The oratory contained no notable works of art. The conversion to a trattoria involved inserting an upper floor, and up there you can examine the surviving religious artwork which is a rather naïve fresco of Our Lady with angels and saints on the intrados of the former triumphal arch.