Who named the planets and why did they name them what they named them?
We use Roman names. Mercury: fast moving, the messenger of the gods. Venus: beautiful, the goddess of love. Mars: blood red, the god of war. Jupiter: bright, dominating the night sky, the king of the gods. Saturn: slow moving, an old god. Some days of the week are named after Roman gods in the Romance languages (e.g. Mardi, Mercredi, Jeudi, Vendredi), and after the equivalent Anglo-Saxon gods in English (Tiw, Woden, Thor, Freya).