San Sebastiano fuori le mura ad Catacumbas (Rome)

 church, basilica, Roman Catholic church, catacombs

Built originally in the first half of the 4th century,[2] the basilica is dedicated to St. Sebastian, a popular Roman martyr of the 3rd century. The name ad catacumbas refers to the catacombs of St Sebastian, over which the church was built, while "fuori le mura" refers to the fact that the church is built outside the Aurelian Walls, and is used to differentiate the basilica from the church of San Sebastiano al Palatino on the Palatine Hill. According to the founding tradition,[3] in 258, during the Valerian persecutions, the catacombs were temporarily used as place of sepulture of two other saints martyred in Rome, Peter and Paul, whose remains were later transferred to the two basilicas carrying their names: whence the original dedication of the church, Basilica Apostolorum ("Basilica of the Apostles"). The dedication to Sebastian dates to the 9th century.
The current edifice is largely a 17th-century construction
www.catacombe.org/it/basilica.htm