The Temple of Portunus or Temple of Fortuna Virilis ('manly fortune') is one of the best preserved of all Roman temples. Its dedication remains unclear, as ancient sources mention several temples in this area of Rome, without saying enough to make it clear which this is.
The temple was originally built in the third or fourth century BC but was rebuilt between 120-80 BC, the rectangular building consists of a tetrastyle portico and cella, raised on a high podium reached by a flight of steps, which it retains.
The temple owes its state of preservation to its being converted for use as a church in 872 and rededicated to Santa Maria Egyziaca (Saint Mary of Egypt). Its Ionic order has been much admired, drawn and engraved and copied since the 16th century. The original coating of stucco over its tufa and travertine construction has been lost.
References:The Church of St Donatus name refers to Donatus of Zadar, who began construction on this church in the 9th century and ended it on the northeastern part of the Roman forum. It is the largest Pre-Romanesque building in Croatia.
The beginning of the building of the church was placed to the second half of the 8th century, and it is supposed to have been completed in the 9th century. The Zadar bishop and diplomat Donat (8th and 9th centuries) is credited with the building of the church. He led the representations of the Dalmatian cities to Constantinople and Charles the Great, which is why this church bears slight resemblance to Charlemagne's court chapels, especially the one in Aachen, and also to the Basilica of San Vitale in Ravenna. It belongs to the Pre-Romanesque architectural period.
The circular church, formerly domed, is 27 m high and is characterised by simplicity and technical primitivism.