It represents one of the best kept building of Ancient Rome. The temple, erroneously called of the Fortuna Virile, is right next to the modern Palazzo dell’Anagrafe del Comune di Roma (Building of the Registry office of the Municipality of Rome), in the site of the ancient port Tiberino. 

It was dedicated to Portunus, god of the fluvial accesses, patron of this side of the Foro Boario assigned to the merchants. The origin of the Temple goes back to the IV or III century BC but the actual aspect goes back, probably to the second half of the II century with remaking of the I century BC. 

The extraordinary conservation status is given to the fact that in 872 it was transformed in the church of S. Maria de Gradellis which became in the XV century S. Maria Egiziaca. The temple rises on a high platform covered with travertine slabs and shows on the main front, four ionic columns; the greater sides present two columns and five semicolumns in tuff of the Aniene as well as the walls of the cell. 

Part of the plaster covering of the architrave with a frieze of festoons hung at branched candlesticks is preserved, while the cornice presents leonine protomi.