Oratorio dei Quaranta Martiri is an ancient ruined oratory dedicated to the Forty Martyrs of Armenia, and is located in the Roman Forum. This is part of the Foro Romano e Palatino archaelogical site, and requires the purchase of a ticket for access.
The oratory is just north of the church of Santa Maria Antiqua, on the other side of the ancient ramp leading to the palaces of the Palatine, and shares its later history. It was probably part of the organization of that church from the start.
It was established no later than the 8th century, and was the result of a conversion of a 1st century building of unknown original function. When it was converted an apse was added.
After its excavation in 1902, the structure was left at the mercy of the weather until the present building with its gabled roof was provided in 1999 in an attempt to avoid the total loss of the frescoes. This is now a prominent and rather ugly feature in many famous views of the Forum. It is often mistaken for Santa Maria Antiqua, which has its own more discreet protective roof to the south.
The 8th and 9th century frescoes in the apse depict the torture and martyrdom of 40 soldiers who were killed for their faith at Sebaste (Turkish Sivas) in Roman Armenia during the persecution of Diocletian in the early 4th century. The left side wall shows a procession of saints, and the right hand one possibly depicts St Anthony of Egypt.
The floor is of re-used marble fragments.
The oratory is not always accessible due to ongoing excavations in the area. However, guided tours were being provided in March and April 2011 (although these did not seem to continue into the summer).