Paul V had a dispute with the astronomer Galileo. In 1616, Paul V was informed of Galileo teaching Copernicus’s theory of a heliocentric universe, which argued that the Earth rotated around the Sun. Such theories were considered heresy by the Catholic Church at the time. While Paul V banned Galileo from teaching the Copernican theory, he nevertheless allowed the astronomer to study it. Later on, Paul V placed Galileo under his protection, declaring that he would not be prosecuted by the Roman Inquisition while he served as pope.