The telescope, known to the Arabians in the Middle Ages, and described by Roger Bacon in 1250, helped Copernicus to prove the revolution of the earth in 1530, and Galileo to substantiate his theory of the planetary system.

Printing, after numerous useless revelations to the world of its resources, became an art in 1438; and paper, which had long been known to the Chinese, was first made of cotton in Europe about 1000, and of rags in 1319.
Gunpowder entered into use about 1320.

As employed by the Genius of the Renaissance, each one of these inventions became a lever by means of which to move the world.

Gunpowder revolutionized the art of war.

The feudal castle, the armor of the Knight and his battle-horse, the prowess of one man against a hundred, and the pride of aristocratic cavalry trampling upon ill-armed militia, were annihilated by the flashes of the canon.