The Ara Pacis Augustae (Altar of Augustan Peace) was commissioned by the Roman Senate in 13 BCE to honor the triumphal return of Emperor Augustus from his campaigns in Spain and Gaul, and to celebrate the peace (Pax Romana) established across the empire. Dedicated in 9 BCE on the northern edge of the Campus Martius in Rome, this monumental marble altar is widely regarded as the supreme achievement of Roman narrative relief sculpture and political propaganda.

Architecturally, the monument consists of an open-air precinct wall enclosing a central sacrificial altar. The marble reliefs adorning the precinct walls fuse the idealism of Classical Greek art with the documentary realism characteristic of Roman art. The grand processional friezes along the upper exterior walls depict the actual inaugural procession of 13 BCE. Unlike the idealized, anonymous figures of the Parthenon frieze, the Roman sculptors portrayed real historical individuals — including Augustus himself, his family (such as Livia and Agrippa), priests, and senators — with recognizable, individual facial features, capturing a specific moment in Roman history.

Other panels depict Roman founding myths, such as Romulus and Remus suckled by the she-wolf, and Aeneas (or Numa Pompilius) offering a sacrifice, directly linking the Augustan dynasty to Rome's divine origins. The famous 'Tellus' (or Pax) panel features a maternal goddess cradling two infants, surrounded by livestock, crops, and personifications of sea and land breezes, symbolizing the fertility, peace, and abundance brought by Augustan rule. Below these narrative panels, a lush lower frieze of scrolling acanthus leaves represents the renewal of nature and cosmic order under the new regime.

The Ara Pacis is historically unique as it celebrates not military conquest itself, but the peace and civil stability that resulted from it. Buried for centuries by silt from the Tiber, the altar was systematically excavated and reconstructed in 1938 under Benito Mussolini, and has been housed since 2006 in a striking contemporary pavilion designed by architect Richard Meier.