Alcalá de Guadaíra Castle is the result of almost 4,500 years of human history. The older archaeological findings take us to the Bronze Age (2nd millennium BCE), when a small walled village settled down on the East edge of the Hill.
The current castle was built during the times of Muslim domination, in the 11th and 12th centuries, although after the Reconquest by Ferdinand III is when it acquired its definitive layout. Important development was still taking place right up to the late 15th and early 16th century.
Today the castle is restored after been abandoned a long time since the 19th century.
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.