Castle Sween is thought to be one of the earliest stone castles built in Scotland, having been built sometime in the late twelfth century. The castle's towers were later additions to wooden structures which have now since vanished.
Castle Sween takes its name from Suibhne, whose name was Anglicised as 'Sween'. He was thought to have built the castle. Suibhne was thought to have been a grandson of Hugh the Splendid O'Neill who died in 1047. In the thirteenth century, the Clan MacSween governed lands extending as far north as Loch Awe and as far south as Skipness Castle on Loch Fyne. In the later half of the thirteenth century the MacSween lands of Knapdale passed into the hands of the Stewart Earls of Menteith.
By the time of the Wars of Scottish Independence the MacSweens entered into the service of King Edward I of England in the hope of recovering their lands from the Earl of Menteith, however when Robert the Bruce became King of Scotland he displaced the MacSweens from their lands. After Robert the Bruce had defeated MacDougall Lord of Lorne in 1308, he then laid siege to Alasdair Og MacDonald in Castle Sween. Alastair gave himself up and was disinherited by Robert Bruce who then granted Islay to Alasdair's younger brother, Angus Og, the king's loyal supporter, who also received the Castle Sween in Kintyre from the King.
In 1310, Edward II of England granted John MacSween and his brothers their family's ancestral lands of Knapdale, (though by then Castle Sween was held by Sir John Menteith). It is possible that this could be the 'tryst of a fleet against Castle Sween', recorded in the Book of the Dean of Lismore, which tells of the attack of John MacSween on Castle Sween.
In 1323, after the death of Sir John Menteith, the Lordship of Arran and Knapdale passed to his son and grandson. In 1376 half of Knapdale, which included Castle Sween, passed into possession of the MacDonald Lords of the Isles, by grant of Robert II of Scotland to his son-in-law John I, Lord of the Isles.
In 1647, during the Wars of the Three Kingdoms, Castle Sween was attacked and burnt by Alasdair MacColla and his Irish Confederate followers.
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.