Now it is not clear what causes forced Nesvizh Prince Nicholas Radziwill ( "Orphan") order in May 1583 to start in place of the old wooden castle building modern Fortress. It is likely that the reason was a sudden fire. However, it is possible that the prince has influenced the practice of European fortification. This is supported by the fact that the winter 1580-81 gg. Radziwill spent in Italy, where he could see with his own eyes and the then properly assess the achievements of the Italian military architecture.