Final answer:
Mercury, known as the messenger god in Roman mythology, was not the patron god of any other deity but was a god of commerce, communication, and travelers. As a quick and agile deity, the planet closest to the Sun is also named Mercury after him.
Step-by-step explanation:
Mercury was not the patron god of Jupiter, Mars, Venus, or Neptune, but was a Roman deity in his own right. Mercury was known as the fleet-footed messenger of the gods. In Roman mythology, Mercury is the god of commerce, communication, travelers, trickery, and is a guide to the underworld. He corresponds with the Greek god Hermes. The question seems to misunderstand the role of a 'patron god', suggesting one god could be the patron of another, which is not consistent with the pantheon's structure.
Mercury's connection with speed and the ability to move swiftly made him an apt symbol for the planet closest to the Sun, also named Mercury due to its swift orbit. As the god of communication and commerce, he was the protector of merchants and traders, as well as travelers. In the arts, Mercury is often depicted with a winged helmet and sandals, highlighting his role as a divine messenger.