Titan (moon)
Titan was discovered on 25 March 1655 by Christiaan Huygens, an astronomer from the Netherlands. Earlier, in 1610, Galileo Galilei had discovered four of Jupiter's moons. This inspired Huygens: he also wanted to discover new moons. Because Huygens had also improved the telescopes of the time, making them a lot better, he thought he might be able to discover a new moon.