The name Skorodom for the ring of slobodas around Moscow before the earthen rampart was built

Until 1637-40, when Tsar Mikhail Fyodorovich had an earthen rampart raised around Moscow, the ring of suburbs encircling the Kremlin, the Bely Gorod and the Kitay-Gorod was known as Skorodom, or Skorodum. Why? In 1588-1592 the villages around Moscow were hastily enclosed with wooden walls, since an invasion by the Crimean khan was expected. Plain wooden houses were put up in haste along the walls, hence "skorodom", the "quick house". The name may also have arisen from the fact that the walls were both planned quickly and built quickly, hence "Skorodum", the "quick thought". In the Time of Troubles the wooden city fence burned down, and in the following decades the posads, suburbs and villages around Moscow came to be called simply the Old Wooden City. The expression Earthen City (Zemlyanoy Gorod) is found only from the middle of the seventeenth century