 The slave raids of Crimeans, however, did not cease until the late 17th century though the construction of new fortification lines across Southern Russia, such as the Great Abatis Line, constantly narrowed the area accessible to incursions.The death of Ivan's sons marked the end of the ancient Rurik Dynasty in 1598, and in combination with the famine of 1601–03 led to civil war, the rule of pretenders, and foreign intervention during the Time of Troubles in the early 17th century.The Polish–Lithuanian Commonwealth occupied parts of Russia, including Moscow.