The term kremlin (also kremnik) is first encountered in chronicles of 1317 in accounts of the construction of the Tver Kremlin, where a wooden city-fortress was erected, which was clayed and whitewashed.<ref>Template:Cite book</ref> The term detinets (such as in the Novgorod Detinets) is considered to be older and was kept in the Novgorod region, while the term krom (such as in the Pskov Krom) was more often used in the Pskov region.Template:Sfn In other Russian regions, such as in the Moscow and Tver regions, fortresses in the center of cities began to use the term kremlin instead,Template:SfnTemplate:Sfn which superseded the term detinets in the 14th and 15th centuries.Template:Sfn
Wooden fortresses were erected everywhere in the Russian state—from the far eastern lands to the Swedish border. They were numerous in the south, where they served as a link of fortified fortification zones cutting off the way to the central regions from Crimean Tatars. Aesthetically wooden fortresses were not inferior to stone ones—and we can regret that the towers of wooden kremlins have not survived to this day. Wooden fortresses were built quickly: in 1638 in Mtsensk fortress walls of Bolshoi Ostrog and Pletny Gorod with a total length of about 3 kilometres with 13 towers and almost one hundred meters long bridge over the River Zusha were erected in 20 days. The town of Sviyazhsk was built similarly during the Kazan campaign in the spring of 1551: fortress walls about 2.5 kilometres long, many churches and houses were erected in a month.
Later on, many Kremlins were rebuilt and strengthened. Thus, the Moscow Kremlin under Ivan III was reconstructed using brick.
In the 16th and 17th centuries, about 30 stone fortresses were built in the Russian state. New kremlins have regular geometric forms in plan (Zaraisky and Tula Kremlins). The Tula Kremlin is unique because it was built in a valley (which was possible because of undeveloped siege artillery of nomad Tatars).
Construction of the Kremlin lasted until the turn of the 17th and 18th centuries. The last kremlin structure – the Tobolsk Kremlin – was built using stone between 1699 and 1717 in the town of Tobolsk (the easternmost kremlin in Russia).
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