Tiversk or Tiversky gorodok (Finnish: Tiurinlinna) was a medieval Russian fortified settlement situated on an island of the River Vuoksi. The fort was 215–300 m long and 40–56 m wide. It gained in prominence in 1323 when the Treaty of Nöteborg established a Novgorodian-Swedish border in the immediate vicinity. It was then mentioned in the Nikon Chronicle in 1404, when the settlement was granted to Prince Yury of Smolensk as an appanage. Seven years later, the fort was sacked and destroyed by the Swedes during one of the Swedish-Novgorodian Wars.
The site of Tiversk was first identified and described by Jacob Groot in 1847. The remnants were excavated in 1888-1891 by Hjalmar Appelgren, Theodor Schwindt and Alfred Hackman, in 1971 by Anatoly Kirpichnikov, and in 1971-1974 by Svetlana Kochkurkina. Most remnants are dated end of the 13th-beginning of the 15th century. In 1890 archaeological works revealed a treasure trove with 13th-15th century Arabic silver coins. Some remnants dated 10th-early 12th century have also been discovered. The ramparts and stone walls of the settlement were 4.5 to 7 metres thick.
References:Celje Castle was once the largest fortification on Slovenian territory. The first fortified building on the site (a Romanesque palace) was built in the first half of the 13th century by the Counts of Heunburg from Carinthia on the stony outcrop on the western side of the ridge where the castle stands. It had five sides, or four plus the southern side, which was a natural defence. The first written records of the castle date back to between 1125 and 1137; it was probably built by Count Gunter. In the western section of the castle, there was a building with several floors. Remains of the walls of this palatium have survived. In the eastern section, there was an enclosed courtyard with large water reservoirs. The eastern wall, which protects the castle from its most exposed side, was around three metres thicker than the rest of the curtain wall. The wall was topped with a parapet and protected walkway.