The Castle of St. George (Castello di San Giorgio) was built from 1395 and finished in 1406 under commission by Francesco I Gonzaga, designed by Bartolino da Novara, one of the most renowned military architects of the time. It has as square plan with four corner towers, surrounded by a ditch with three entrances, each one with a drawbridge. In 1459 architect Luca Fancelli, commissioned by marquis Ludovico III Gonzaga, who assigned several rooms of the Corte Vecchia for the Council of Mantua called by Pope Pius II, restored the castle, which lost definitely lost its military and defensive function.
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.