The 7th planet - Uranus was discovered on this date, completely by accident. British astronomer William Herschel was performing a survey of all stars of at least magnitude 8 from slightly too faint to see with the eye, in other words. That's when he noticed a very faint object - only barely within the limit for viewing with the eye - that that moved in front of the fixed stars. This movement clearly demonstrated it was closer to us than the stars. At first, he thought he had found a comet. Later, he and others realized it was a new planet in orbit around our sun, the first new planet discovered since ancient times.
Herschel proposed to name the object Georgium Sidus, after King George III, but those outside of Britain weren’t pleased with the idea. Instead, on the suggestion of astronomer Johann Elert Bode, astronomers decided to follow the convention of naming planets for the ancient gods. Uranus an ancient sky god, and one of the earliest gods in Greek mythology was sometimes called Father Sky and was considered to be the son and husband of Gaia or Mother Earth.