Mercury is the closest planet to the sun. As such, it circles the sun faster than all the other planets, which is why Romans named it after the swift-footed messenger god Mercury.
Mercury was known since at least Sumerian times roughly 5,000 years ago, where it was often associated with Nabu, the god of writing. Mercury was also given separate names for its appearance as both a morning star and as an evening star.
Greek astronomers knew, however, that the two names referred to the same body. Heraclitus believed that both Mercury and Venus orbited the Sun, not the Earth.
According to this passage:
|Greek astronomers had two names for Mercury.|
|The Romans named Mercury after one of their gods because Mercury is the closest planet to the sun.|
|Mercury is closer to the sun than the Earth is to the sun.|
|Mercury was unknown before 5,000 years ago.|