In the history of the development of science and technology, there are periods when some innovation makes a radical revolution and everything that was created over the course of decades becomes obsolete, opening the way for something new. In shipbuilding, such innovations include the appearance on ships, first of sails, and then of artillery. The revolution, closely related to the development of technology and metallurgy, was brought about by the steam engine that appeared on ships at the beginning of the nineteenth century, and half a century later by the protection of ships from enemy artillery with armor.