The cathedral dedicated to Saint Justin of Chieti was probably founded in the 8th century and, according to tradition, was re-built by bishop Teodorico I in 840, after the sack by Pepin of Italy. It was again re-built by bishop Attone I in 1069, but of that building only parts of the Romanesque crypt remain. The church was beautified in the 14th and 15th centuries thanks to different bishops. The first three floors of the bell tower were erected in 1335 by Bartolomeo di Giacomo and in 1498 Antonio da Lodi built its bellcote and tented roof. The church was decorated again in the 17th century in the Baroque style. The 1703 Apennine earthquakes destroyed the tented roof of the bell tower and damaged the church, whose aspect was changed by the archbishop Francesco Brancia between 1764 and 1770. In the early 20th century the architect Antonio Cirilli consolidated the bell tower and extensively modified the exterior. The crypt hosts the relics of Saint Justin of Chieti. Close to the cathedral there is the Baroque oratory of the Mount of the Dead Brotherhood, the oldest catholic fraternity of Chieti that was officially acknowledged by Pope Innocent X in 1648.