Raseborg Castle

Raseborg's founding is debated. One account credits Hermann of Dorpat, successor of Albert of Riga, and the Livonian Brothers of the Sword, building in the wake of the Livonian Crusade and naming the site Ratzeburg after the Bishopric of Ratzeburg; another credits the magnate Bo Jonsson Grip, with the castle's first phase thought to have been completed sometime between 1373 and 1378. The earliest surviving written mention of the castle dates from 1378. Built on a small island at the head of a sea bay, its purpose was probably to command the sea approach to the Gulf of Finland and the shipping route to Reval. Historians think it was raised in three stages between the 14th and 16th centuries. On Bo Jonsson's death, the castle reverted to the crown in 1388 along with most of his other fiefs.

The castle's strength and position made it a prize during the unrest of the following century, and it changed hands repeatedly: held by Karl Knutsson (Bonde) in 1442–48 and again in 1465–68, by the knight Laurens Axelsson (Tott) from 1469 to 1482, then by his widow Katarina Eriksdotter Nipertz and their children until 1487, and afterwards by Knut Posse. Tönne Eriksson (Tott) served as bailiff there from 1492 to 1513, a post later held by Krister Klasson (Horn). Swedish and Danish forces, and pirates, fought over control of the castle during the Middle Ages. In 1520 Raseborg came under Danish overlordship along with the rest of Sweden; on Advent Sunday, 16 December 1520, the Danes beheaded Bishop Hemming Gadh and Nils Eskilsson Banér on the gallows hill outside the castle walls.

Fighting for Gustav Vasa, the brothers Erik and Ivar Fleming took Raseborg in 1523, and Erik held it in fief until 1540. By then the castle was so dilapidated that Gustav Vasa judged it not worth repairing; in 1527 he decided instead to build a new castle where the sailing route was better, and to found a town there where the local population could trade hops, salt and other goods without travelling to Reval. That town was probably Ekenäs, which Erik Fleming began building in 1529 at the mouth of Pojo bay. After Erik Fleming lost the old castle in 1540, the king's bailiffs managed it for a time and carried out repairs, but once administration of the surrounding six parishes was transferred to the Helsingfors crown bailiwick in 1552, Raseborg lost its administrative role and was no longer treated as strategically significant. The sea around it was also retreating: postglacial land uplift steadily lowered the water level, making the harbour harder to reach by boat, which historians count among the main reasons the castle lost its importance.

Raseborg's active life is usually bracketed 1370s to 1553, the year by which nearby Helsinki, founded in 1550, had begun to eclipse it strategically. The fuller record carries the story three years further: eighteen men still manned the castle's rolls in 1557, a strength matching some years of the 1540s, but maintenance had fallen behind, and in spring 1558 part of the structure gave way — vaulting collapsed, bringing down the roof of the beer cellar with it. The castle was abandoned for good that year.

The castle's plan is roughly D-shaped, with a large round donjon at the curved end, a straight keep and an inner bailey, ringed by two outer baileys whose outer wall carried a square tower and a barbican. Restoration work began in the 1890s, and the ruins are today a Cultural Heritage Site of National Significance and a registered archaeological site in Finland, standing within the modern municipality of Raseborg. They are open to the public in summer, and each July the site hosts the Raseborg Summer Theatre — one of the largest open-air stages in Finland, founded in 1966 — with performances in Swedish often tied to the castle's own history.