Since 1986 Gravina Cathedral has served as a co-cathedral of the Diocese of Altamura-Gravina-Acquaviva delle Fonti. It was built here at the end of the 11th century by Humphrey of Hauteville, Count of Apulia and Calabria, and thus lord of the town. This church was destroyed in the years 1447-1456 by a fire followed by an earthquake, after being refurbished in a Renaissance-Romanesque style. Of the original church only a few Byzantine capitals and frescoes remain. The present cathedral was built in the thirty years following, under the supervision of the bishop Matteo d'Aquino.
The main façade has a large rose window. The altarpieces are made from 17th-century intarsia with polychrome marble and mother of pearl. The ceiling has framed canvases. The church has an altarpiece carved in Bitonto stone (1468) by Guido da Guida. There is a San Michele (1538) carved in mazzaro, a local stone, and attributed to Stefano da Putignano. Along the north nave is a Byzantine fresco of the Madonna del Piede. The oak choir-stalls were made in the 15th century and rebuilt by Bishop Antonio Maria Manzolio (1581-1593).
The adjacent sacristy has a ceiling refurbished by bishop Manzolio, and elaborate presses. The bell-tower was built from a Norman watch tower.
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.