Its 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.

[2] Originally named Church of the Holy Trinity,[3] in the 15th century it was re-dedicated to St Donatus.

It has three radially situated apses and an ambulatory around the central area, surmounted by circular gallery.

[7] Among the fragments which are built into the foundations it is still possible to distinguish the remains of a sacrificial altar on which is written IVNONI AVGUSTE IIOVI AVGUSTO.

[5] The use of the church has varied during its lifetime; during the rule of the Republic of Venice it was a warehouse, as well as during the French occupation and under the Austrians.