A church at the site of current Santa Marta was present by the 13th century, originally dedicated to St Calimero. In 1386, it housed the flagellant Confraternity of the Disciplini of St Marta, who added a hospice and rededicated the church. The church has been refurbished over the centuries. The facade dates to 1720–1730.
The interior ceiling has a late 17th-century fresco, depicting the Glory of St Martha, by Giovanni Battista and Carlo Pozzo, and the church houses a 17th-century processional statue on the main altar of the Madonna of the Rosary and Child. The altar has 16th century marble sculpture busts of the apostles; the altar was refurbished in 1816 likely by Giuseppe Bovara. The lateral altars have statues of Santa Marta and San Antonio di Padova.
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.