Although it had been observed multiple times, it took until the year 1781 for Uranus to be officially discovered as a planet. Sir William Herschel observed the planet on March 13, 1781. He initially thought it was a comet and reported it as such. Within two years, however, it was widely accepted as a new planet.
Herschel was asked to name the new planet. He first called it Georgium Sidus (George's Star or Georgian Planet), because he thought that naming planets after mythological gods was antiquated and didn't fit with the new era.
Unsurprisingly, the name George was not popular outside of Britain and very quickly people were trying to come up with alternative names. Some people wanted to name it after Herschel, but eventually the name Uranus was reached. In mythology, Uranus is the Latinized version of the Greek god Ouranos, the god of the sky.