The development of cannons led to the decline in importance of [[castle]]s after the [[Medieval]] period, as troops in such immobile fortified positions could be very easily worn down by artillery fire. By the 17th century the "art" of fortification had become a science. | The development of cannons led to the decline in importance of [[castle]]s after the [[Medieval]] period, as troops in such immobile fortified positions could be very easily worn down by artillery fire. By the 17th century the "art" of fortification had become a science. |