While it's impossible to say for sure who *discovered* Jupiter, as it's visible to the naked eye, ancient civilizations have recorded observations of the planet for millennia.

* Ancient Babylonians: Some of the earliest recorded observations of Jupiter come from Babylonian astronomers, dating back to the 7th century BC.

* Ancient Greeks: Greek astronomers named the planet after Zeus, the king of the gods, and studied its movements.

So, while we can't pinpoint a single individual, it's safe to say that Jupiter has been observed and understood by humans for thousands of years.