Frusinum amphitheatre, Roman amphitheatre remains in Frosinone, Italy

The Frusinum amphitheatre lies at the foot of the hill of today's historic centre, near the Cosa river where the Via Latina crossed it. Its walls emerged in February 1965 during construction of residential buildings; half the structure remains beneath a 1960s apartment block and half probably lies intact under the roadway of Viale Roma.

The structure dates from the late 1st to early 2nd century CE, a period of intense building activity across the Roman Empire. Systematic excavations in the mid-1960s uncovered the remains and revealed details about the original scale and construction methods.

The name Appretiatum, used for the site by the 11th century, appears in a donation act of 10 May 1060, in which Leone and Gregorio granted properties outside the castle of Frosinone to abbot Giovanni of Casamari, including land with old and new walls near the Cosa. The ruins were linked to the vanished churches of San Giovanni and San Silvestro.

The ruins are not visitable: half lies beneath a 1960s apartment block and half under the roadway of Viale Roma. Visible masonry stands between the building's support pillars and has degraded over decades; recovery work began only in 1996. View the remains from the public street outside.

Medieval documents mentioned this structure centuries before its physical excavation, showing that its reputation lived on in local memory and record-keeping. This written record helped archaeologists later pinpoint and investigate the exact location.