Saturn has 53 natural satellites, also known as moons, as of 2014. It has nine provisional moons, defined as moons whose discovery is awaiting confirmation by the International Astronomical Union.
Christiaan Huygens discovered Saturn's moon Titan in 1655, the first recorded discovery of a moon orbiting Saturn. Giovanni Domenico Cassini discovered the next four moons, finding Iapetus in 1671, Rhea in 1672 and Dione and Tethys in 1684. Titan is the largest of Saturn's moons and the second-largest moon in the Solar System. Its atmosphere is similar to the atmosphere of prehistoric Earth. Many of Saturn's smaller moons orbit near one another; sometimes, they exchange orbits.