Catacomb of San Nicomede
The Catacomb of San Nicomede was a catacomb at the start of the via Nomentana near the modern Porta Pia in the Nomentano quarter, though its precise location is still unknown.
Except the Notitia ecclesiarum urbis Romae, the ancient literary sources state that Saint Nicomedes was buried near the gate to the via Nomentana, now Porta Pia.
His legendary 'passio' states he was buried in land belonging to the presbyter Justus "beside the walls [on] via Nomentana', whilst the biography of pope Boniface V in the Liber Pontificalis refers to the construction of a basilica on the martyr's tomb, whilst that of Pope Adrian I states he restored a church dedicated to that saint "outside the porta Nomentana".
From Antonio Bosio to the 20th century, several galleries have been found on the catacomb's presumed site, but none have been definitively identified as this catacomb:
