Ara Pacis, meaning the Altar of Peace, is a marble altar erected in 9 AD by the emperor Octavian August in memory of the end of long civil wars and peace (the famous Pax Romana). It is a substantial structure made of Greek white marble. It includes not only the sacrificial altar itself, but also a six-meter high fence decorated with a frieze immortalizing the procession on the occasion of the altar's dedication. This and other decorations - allegorical figures, illustrations of myths about the history of Rome, floral motifs - were to show the emperor in the role of the renovator of Rome, ensuring peace, prosperity and happiness.
The modern altar is a reconstruction. The foundations of the original are now in the basement of the Palazzo Ottoboni Fiano Almagià. The monument was unveiled again on the occasion of the 2000th anniversary of the birth of Octavian August. He was placed near the mausoleum bearing his name. Since 2006, the Altar of Peace has been protected by a controversial, modern pavilion erected by the American architect Richard Meier.