It is not known who first discovered Jupiter. The planet has, however, been recognized since ancient times. Ancient astronomers named it after the Roman god Jupiter, who was the head of the gods.
According to Universe Today, Jupiter can be seen with the naked eye and does not require a telescope for viewing. Jupiter has been tracked by ancient astronomers including the ancient Greeks and Romans for thousands of years. However, Jupiter was discovered to be a planet during the time of Nicolaus Copernicus in the 16th century. During this time, Copernicus developed a new astronomical model where the sun was the center of the universe rather than the Earth. The Earth was determined to be a planet. Using a telescope, Galileo confirmed the Copernican model and found that Jupiter was a planet by observing moons orbiting Jupiter.