It is hard to say who first discovered Mars, but the planet was known to Egyptian astronomers and recorded by them as far back as 1534 BC. They also knew the location and orbits of many other planets as well.
Ancient Egyptian astronomers recorded sightings of Mars. In 1534, the astronomers were noting the planets retrograde motions. Those are the earliest recorded sighting of Mars. If earlier star gazers previously discovered the planet, their names are lost in history.