Novgorod Kremlin (Detinets) stands on the left bank of the Volkhov River. It is part of the UNESCO World Heritage Site of Historic Monuments of Novgorod and Surroundings. The compound was originally the site of a pagan burial ground upon which the first bishop of Novgorod, Ioakim Korsunianin built the Cathedral of Holy Wisdom upon his arrival in the area in 989 or so. Thus the compound was and remained largely an ecclesiastical site, although many Novgorodian boyars built their houses in the southern part of the Detinets.
The first reference to fortifications on the site dates to 1044, with additional construction taking place in 1116. These were probably earthen embankments topped by a wooden palisade, although stone towers and walls were built in 1302. Archbishop Vasily Kalika (1330–1352) rebuilt the stone wall along the eastern side of the Detinets in 1331-1335. The rest was completed in stone only in 1400. Part of Vasily"s walls collapsed into the Volkhov River in 1437 and were rebuilt by Archbishop Evfimy II (1429–1458).
The current fortress was built between 1484 and 1490 by Muscovite builders in the wake of Grand Prince Ivan III"s conquest of the city in 1478; a third of it was paid for by the Novgorodian archbishop Gennady, a Muscovite appointee (1484–1504). It is a large oval 545 meters long and 240 meter wide with nine surviving towers (three additional towers have not survived). The tallest tower, the Kokui tower is capped by a silver dome. It was built in the eighteenth century and its name is of Swedish origin. Today it is possible to enter this tower and climb to the top. The walls are 1,487 meters in circumference.References:
First record of Kastelholma (or Kastelholm) castle is from the year 1388 in the contract of Queen Margaret I of Denmark, where a large portion of the inheritance of Bo Jonsson Grip was given to the queen. The heyday of the castle was in the 15th and 16th centuries when it was administrated by Danish and Swedish kings and stewards of the realms. Kastelhoma was expanded and enhanced several times.
In the end of 16th century castle was owned by the previous queen Catherine Jagellon (Stenbock), an enemy of the King of Sweden Eric XIV. King Eric conquered Kastelholma in 1599 and all defending officers were taken to Turku and executed. The castle was damaged under the siege and it took 30 years to renovate it.
In 1634 Åland was joined with the County of Åbo and Björneborg and Kastelholma lost its administrative status.