The Cathedral Church of Saint German was built in 1879–84. The Patron of the Cathedral, St German of Man, was a Celtic missionary and holy man who lived from about 410 to 474.
The original cathedral of St German was inside the walls of Peel Castle and was built sometime in the 12th century when St Patrick's Isle was in the possession of Norse kings. At that time the church followed the Sarum Rite, prevalent throughout much of the British Isles. Around 1333 the Lords of Man refortified St Patrick’s Island and occupied the church as a fortress. In 1392 William Le Scroop repaired the Cathedral.
The building fell into ruin in the 18th century. After a considerable period of debate over who owned the ruins and site, it was decided not to rebuild that cathedral. The present building was constructed in 1879–84 to replace St Peter's Church in Peel's market place. In 1895, the bishop consecrated his chapel at the bishop's palace as pro-cathedral and instituted a chapter of canons with himself as Dean. That arrangement (bishop as dean) persisted even after the consecration of the new cathedral.
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.