All of Bornholm’s round churches were build between 1150-1250, the same period as the ruin Hammershus. The churches were originally built as a combination of church and fortress.The middle Ages was a rather chaotic period, there were pirates in the Baltic Sea and the Crusades against Estonia and Latvia. At the time when the churches were built, they were owned by Archbishop Eskil who owned 2/3 of the island and it is believed that he is the builder of the churches.
Østerlars Church is a historical building located just north of the village of Østerlars, 5 kilometres (3.1 mi) south of Gudhjem. It is the largest of the island’s four round churches. Built in about 1160, it was dedicated to St. Lawrence. It consists of an apse, an oval chancel, a large round nave and has three stories. There is evidence the church was once fortified, the top storey serving as an open shooting gallery.
Nyker Kirke is located in the village of Nyker some 7 km from Rønne. Built in the Romanesque style with two storeys, it contains frescos from various periods and a pulpit with 17th century-panels. Like Bornholm’s other medieval churches, Nyker Kirke was built in the 12th century but is normally considered to be the youngest of the island’s four round churches. It was originally called “Ecclesia Omnium Sanctorum” (All Saints Church). The present name dates from the middle of the 16th century. Photo by Hubertus
Nylars Church, the oldest of Bornholm’s four round churches. Built around 1165, the church was dedicated to St Nicholas. The three storeys are built of fieldstone and with windows and door frames of limestone. The original defensive systems are largely intact. The porch is from 1879. The church first belonged to the Archbishopric of Lund, then came under the Danish crown at the time of the Reformation. In the 19th century, it become fully independent. Photo by Szymon Nitka, Poland
Olsker Church, the highest of Bornholm’s four round churches, rising 13 metres from its base to the top of the conical roof, the church is built of local granite fieldstone with limestone door frames. Standing on a hilltop at a height of 112 metres above sealevel, it was built as a stronghold to defend the surrounding area. The openings in the wall on the upper storey were designed for shooting arrows or throwing stones at the enemy. There was also a platform with a parapet which was used for defensive purposes. The church was also equipped with a hanging gallery, supported on beams projecting from the walls of the round tower.