Galileo Galilei (1564-1642) was an Italian astronomer, physicist, and mathematician. He is considered one of the most important figures in the scientific revolution of the 16th and 17th centuries. Galileo was born in Pisa, Italy, and was the eldest of six children. He attended the University of Pisa where he studied medicine and mathematics but left without completing his degree.

In 1609, Galileo heard about the invention of the telescope in the Netherlands and built his own. He used it to observe the night sky and made several important discoveries, including the moons of Jupiter and the phases of Venus, which supported the heliocentric theory of the solar system proposed by Copernicus.

Galileo's support of the heliocentric theory brought him into conflict with the Catholic Church, which held that the Earth was the center of the universe. In 1632, Galileo published his book, "Dialogue Concerning the Two Chief World Systems," which argued for the heliocentric view. This led to his trial by the Inquisition and he was placed under house arrest for the remainder of his life.

Despite this, Galileo continued to work on his scientific theories and made important contributions to the fields of physics, mathematics, and astronomy. He formulated the laws of motion and the law of falling bodies, which were later incorporated into Newton's laws of motion.

Galileo's work had a profound impact on the development of modern science and his discoveries and theories continue to be studied and celebrated today.