The sky often has important religious significance. Many religions, both polytheistic and monotheistic, have deities associated with the sky. The daytime sky deities are typically distinct from the nighttime ones. Stith Thompson's Motif-Index of Folk-Literature reflects this by separating the category of "Sky-god" (A210) from that of "Star-god" (A250). In mythology, nighttime gods are usually known as night deities and gods of stars simply as star gods. Both of these categories are included here since they relate to the sky. Luminary deities are included as well since the sun and moon are located in the sky. Some religions may also have a deity or personification of the day, distinct from the god of the day lit sky, to complement the deity or personification of the night. Daytime gods and nighttime gods are frequently deities of an "upper world" or "celestial world" opposed to the earth and a "netherworld" (gods of the underworld are sometimes called "chthonic" deities). Within Greek mythology, Uranus was the primordial sky god, who was ultimately succeeded by Zeus, who ruled the celestial realm atop Mount Olympus. In contrast to the celestial Olympians was the chthonic deity Hades, who ruled the underworld, and Poseidon, who ruled the sea. Any masculine sky god is often also king of the gods, taking the position of patriarch within a pantheon. Such king gods are collectively categorized as "sky father" deities, with a polarity between sky and earth often being expressed by pairing a "sky father" god with an "earth mother" goddess (pairings of a sky mother with an earth father are less frequent). A main sky goddess is often the queen of the gods and may be an air/sky goddess in her own right, though she usually has other functions as well with "sky" not being her main. In antiquity, several sky goddesses in ancient Egypt, Mesopotamia, and the Near East were called Queen of Heaven. Neopagans often apply it with impunity to sky goddesses from other regions who were never associated with the term historically. Gods may rule the sky as a pair (for example, ancient Semitic supreme god El and the fertility goddess Asherah whom he was most likely paired with). The following is a list of sky deities in various polytheistic traditions arranged mostly by language family, which is typically a better indicator of relatedness than geography. Speakers of Indo-European languages Proto-Indo-European Dyeus, the chief sky father