This paper retraces the history of the motifs carved on the friezes of the porticoes and hemicycles of the Forum of Augustus. The work is based on the analytical study of hundreds of architectural fragments preserved in the deposits of the Museum of the Imperial Forums and in the archaeological area of the Forum, which for the first time made it possible to understand in detail the decorative syntax of the motifs and to acchieve a graphic reconstruction of them. The systematic research of comparanda, carried out within a wide chronological interval between the sixth century BC and the Late Antiquity, allows to reconstruct the genesis of these motifs from the earliest models to the attestations in the imperial ornamental repertoire. The data obtained from this research are fundamental to understanding the choices made by the architects of the Forum of Augustus regarding the selection of decorative models and their modulation in the various architectural orders housed in the complex.
