Derry's walls were originally built by the Irish Society between 1613 and 1619. They were built with the intention of protecting the Scottish and English planters that had moved to Ulster as part of the Plantation of Ulster that had been established by James I. It was a direct consequence of the previous settlement being destroyed by Irish chieftain Cahir O'Doherty during O'Doherty's rebellion. As a result of the building of the city's defences by the Irish Society, which was a consortium of livery companies based out of the City of London, the city was officially renamed Londonderry in the 1613 royal charter. This is what has subsequently led to the naming dispute for the city and county of Derry/Londonderry.
The walls are at the centre of the historic city of Derry and within them are a number of Derry's most important landmarks including the Apprentice Boy's Hall and St. Columb's Cathedral.
The walls are about 1 mile in circumference and contain many of the city's most important landmarks. The entire length of the walls is fully accessible on foot. There are seven gates in total, four of which were built at the same time as the walls themselves and three were added later.
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.