Before the arrival of the Teutonic Knights, Koknese was the site of a wooden hill fort inhabited by the Balts. In 1209 Bishop Albert of Riga ordered the construction of a stone castle at the site, naming it Kokenhusen. For the first 50 years of its existence, Koknese was solely used as a defensive fort, but by 1277, Koknese had enough population to receive city rights. Koknese also became a member of the Hanseatic League thanks to its strategic location on the Daugava trade route.
The castle was heavily contested between Polish, Swedish and Russian forces in the 16th and 17th centuries. It changed hands many times, while the native inhabitants endured periodic slaughter, capture, and famine. In 1701, during the Great Northern War, Koknese was finally blown up by retreating forces to avoid the strategic castle falling into advancing Russian hands. The castle was never rebuilt and fell to ruin.
In 1900, a park was established around the castle ruins, and Koknese became a popular summer resort. The area was known for its scenic waterfalls, cliffs, and look-outs. In 1965, the Soviet government built Pļaviņas Hydro Power Plant in the town of Aizkraukle. The reservoir flooded the entire length of the Daugava to Pļaviņas. Koknese Castle, once sitting atop a high bluff, was placed at the river's edge, while the scenic Daugava valley was submerged.
References:Visby Cathedral (also known as St. Mary’s Church) is the only survived medieval church in Visby. It was originally built for German merchants and inaugurated in 1225. Around the year 1350 the church was enlarged and converted into a basilica. The two-storey magazine was also added then above the nave as a warehouse for merchants.
Following the Reformation, the church was transformed into a parish church for the town of Visby. All other churches were abandoned. Shortly after the Reformation, in 1572, Gotland was made into its own Diocese, and the church designated its cathedral.
There is not much left of the original interior. The font is made of local red marble in the 13th century. The pulpit was made in Lübeck in 1684. There are 400 graves under the church floor.