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An artist's rendering of the hypothetical impact of a planet like Theia and Earth. (Public Domain)

Theia—Greek Goddess of Light, the Sun, the Moon, and Wisdom


The Olympian gods are well known to most people in the Western world. A lesser-known deity is Theia. Theia is the primordial Greek goddess of light. She was considered one of the Titans. She is said to have been the wife of Hyperion, Titan-god of the sun, and to have given birth to Helios, the primary Greek god of the sun, Selene, goddess of the moon, and Eos, goddess of the dawn. She was also a goddess of sight and wisdom. Although she appears to have faded as a prominent deity among the ancient Greeks, her offspring likely influenced the development of Apollo and Artemis. Her legacy lives on today, in that light and understanding are still coupled in the Western mind. Also, Theia is the name for a hypothetical proto-planetary body which collided with Earth to form the moon in the early history of the solar system.

Mythological Background

Understanding the role of Theia requires understanding her mythological background. Like all cultures, the ancient Greeks originally understood the world through myths. Myths are stories which explain the meaning of the world more than they describe the mechanisms of natural processes which shape the world. This is what makes mythology different from science.

Science deals with descriptions of mechanisms by which the world operates. Mythology is about what the world means for human life. This is not to say that science is not also a mythology in some sense. This is also not to say that the ancients did not practice science in some sense, there is some overlap. Nonetheless, the way we arrive at the scientific story of the world differs from the way the ancients arrived at the mythological story of the world.

There are multiple versions of the ancient Greek creation story, but they all have in common a sequence that goes like the following.

First, there was chaos. The world was formless. After a while, out of chaos came Gaia, a personification of the earth, Tarturus, a personification of the underworld, Eros, the god of love which could be thought of as a personification of the energy that causes change in the universe, and Pontus, an early god of the sea.

Anselm Feuerbach: Gaea (1875). Ceiling painting, Academy of Fine Arts Vienna. (Public Domain)

Anselm Feuerbach: Gaea (1875). Ceiling painting, Academy of Fine Arts Vienna. (Public Domain)

Out of Gaia arose Uranus, the god of the sky. Gaia and Uranus then mated which gave rise to the Titans which included Hyperion, Theia, and Cronus among other early gods. The Titans are depicted as human in form. Gaia and Uranus, however, produced other offspring as well. These were the Cyclopes, one-eyed creatures of great strength and skill with metalworking, and the Hecatoncheires, creatures that had a hundred arms and fifty heads.

These creatures were considered so monstrous by Uranus that he imprisoned them deep within Gaia. Gaia resented the mistreatment of her children and plotted to overthrow Uranus. This plot involved the youngest of the male Titans, Cronus, who used a sickle made by Gaia to castrate Uranus, his father. Hyperion is said to have been one of the Titans to restrain Uranus as Cronus did the deed.

After the overthrow of Uranus, Cronus became the new ruler of the universe. It is said in Greek mythology that Cronus presided over a time of great peace and prosperity for the world. It was probably during or after this time that Theia the goddess of light married Hyperion the god of the sun and they had their celestial children.

There was one problem, however. Cronus did not release the Cyclopes and the Hecatoncheires from their prison in Tartarus. This angered Gaia. There was also a prophecy that Cronus would be overthrown by one of his children. Cronus, because he knew one of the offspring of Rhea, his wife, would overthrow him, would snatch and eat each new child to which Rhea gave birth.

Gaia was intent on overthrowing Cronus, so when Zeus was born, she helped Rhea hide the new-born god in Crete. When Zeus was fully grown, he forced his father to vomit out his siblings. After this proceeded the great battle of the gods.

The battle was between Mount Olympus, the seat of Zeus and the other Olympian gods, and Mount Othrys, the mountain from which the Titans ruled the universe. The Titans who warred against Zeus were all imprisoned in Tartarus. Some Titans, however, such as Oceanus and Theia, remained neutral. Because of this, it is likely that Theia escaped imprisonment.

Theia’s Connection with Light

There is little mention of Theia in later Greek myths, but what appears to be the case is that she was a goddess associated with light, sight, and wisdom. She was able to manipulate light and all her offspring were in some way involved in the creation or manipulation light. She was also associated with the shimmering air of the bright blue upper atmosphere. Furthermore, gemstones and precious metals, like gold and silver, were said to have their shimmer because of her.

The ancient Greeks believed that they could see because of beams of light protruding from their eyes. This was of course before later Greek philosophers, like Aristotle, argued otherwise. Thus, it makes sense that they would have made Theia a goddess of both sight and light.

She was also associated with wisdom and prophecy and had a shrine in Phthiotis in Thessaly dedicated to her. It is possible that Theia had an associated oracle acting as her mouthpiece not unlike the Oracle of Delphi. Although she does not play a major role in later Greek myths, she does have prominent children.

Theia’s Offspring—the Sun, the Moon, and the Dawn

Theia, with her husband Hyperion, had three offspring, Helios (the sun), Selene (the moon), and Eos (the dawn). Theia’s offspring are all related to phenomena involving light. The sun is the main source of light during the day. The moon is a main source of light on nights where the moon is in the right phase, and the dawn is when the light of the sun begins to appear on the perimeter on the of the world before the actual sun rises. Even Theia’s husband Hyperion is an early sun god.

Theia’s offspring are another reason that Theia is considered the goddess of light because they could all in some way manipulate light. Light is their common denominator.

Three paintings showing three deities of Greek mythology, the three offspring of Theia and Hyperion. From left to right: Helios (or sun god Apollo) personifying Day, Eos (or Hesperos) embodying Dawn, and Selene (or Diana, Luna) personifying Night or the Moon. (Public domain)

Three paintings showing three deities of Greek mythology, the three offspring of Theia and Hyperion. From left to right: Helios (or sun god Apollo) personifying Day, Eos (or Hesperos) embodying Dawn, and Selene (or Diana, Luna) personifying Night or the Moon. (Public domain)


Helios was believed by the ancient Greeks to cross the sky each day in a chariot drawn by four flying horses. It was said that when not in the sky he resided in a palace in Oceanus, the world-encircling river. Each day, he would emerge out of his palace in the east and ride across the sky to the west. Helios is implicated in several other Greek myths involving gods and humans.

Detail from card 44 of the Mantegna Tarocchi, depicting Helios the sun god of Greek mythology and his chariot, from the Uffizi gallery in Florence. (Public domain)

Detail from card 44 of the Mantegna Tarocchi, depicting Helios the sun god of Greek mythology and his chariot, from the Uffizi gallery in Florence. (Public domain)

One of these myths is that of Prometheus who stole fire from the gods and gave it to humanity. According to the story, after Zeus became lord of the universe, he tasked his sons Prometheus and Epimetheus with creating humans and animals, respectively. Epimetheus lavishly spent his gifts on his creation. Epimetheus used so many gifts on animals however, that he forgot to leave a gift for humans. As result, humans were deprived of physical gifts compared to the animals.

Prometheus had pity on his creations and decided to give them fire. Fire was forbidden to humans and was reserved for the gods alone. Prometheus, however, was intent on giving humanity a gift to make up for his brother’s mistake. One morning, as the sun god rose into the sky, Prometheus took some fire from the chariot of Helios and gave it to humanity. In this way, Helios is implicated in the origin story of humanity in Greek mythology.

What is interesting about this connection between Helios and the fire that Prometheus gave humankind to give them an advantage is the role the sun played in the rise of civilization. After the rise of agriculture, the yearly motion of the sun in the sky from solstice to solstice and equinox to equinox became very important to early farmers to ensure that they planted and harvested in time to avoid starving.

Prometheus is often understood in modern times as a metaphor for human progress. It was agriculture that allowed for the rise of civilization and technological progress. Agriculture also relies heavily on the motion of the sun throughout the year. As a result, it is fitting that the sun god plays a role in the story. It could be said that it is because of the sun that we have civilization.

Later in Greek history, the role played by Helios as a god associated with the sun and with light increasingly became taken over by the Olympian god Apollo. Apollo is the Olympian god associated with light, reason, and music, among other things. He also became connected to the sun and other things associated with Helios.

How does this all relate Theia? Helios was the offspring of Theia. As result, it could be said that all the contributions made by Helios are in part thanks to Theia his mother, the goddess of light and wisdom. Apollo, therefore, is also connected to Theia.

Another interesting connection to history is that the rise of agriculture also occurred because humans were able to use their understanding of the natural world to learn how to influence the growth of plants and animals. Thus, before Helios could allow for agriculture to flourish, humanity needed to receive wisdom from Theia to develop agriculture.


Selene, the goddess of the moon, was also believed to ride a chariot through the sky. She is often depicted as a woman with a crescent moon on her head. The Romans had two temples to her Latin counterpart, Luna. One was on Palatine Hill and the other was on Aventine Hill in Rome.

Selene, the goddess of the Moon, with her cloak billowing above her head. (antmoose/CC BY 2.0)

Selene, the goddess of the Moon, with her cloak billowing above her head. (antmoose/CC BY 2.0)

One Greek story in which Selene is prominent involves her falling in love with Endymion. Zeus cast him into eternal sleep, but she would visit him every night. She ended up giving birth to 50 daughters by him.

Over time, Selene became associated and sometimes identified with Artemis, the goddess of the hunt, childbirth, and chastity. The association between the moon and women, in many mythologies not just Greek mythology, may be related to the fact that the moon has a monthly phase cycle which echoes the monthly rhythm of a woman’s menstrual cycle.


Eos, goddess of the dawn, was responsible for opening the gates of dawn to make way for Helios as he rode into the sky on his chariot. She is given the epithet, “rosy fingered.” She was also responsible for dispersing the night to make way for morning.

Eos is featured prominently in two stories. In one story, she falls in love with a mortal named Tithonus. She asks Zeus to grant him eternal life but forgets to also ask for eternal youth. As a result, Tithonus grows older and older and weaker and weaker, but is unable to die.

In another story, Eos has an affair with the war god Ares. After this affair, Aphrodite, Ares’ lover and goddess of love, curses Eos so that she will always be in love but never find true love. One of the results of this endless search for love was apparently Memnon, a legendary king of Ethiopia who fought Achilles in the Trojan War and was also the son of Eos.

Although these are the children of Theia and not Theia herself, it could be said that these themes all relate to Theia. Eos would prepare the way for Helios to bring sunlight. Selene would bring moonlight. The common theme is light which in the original Greek myth came from Theia.

Theia—Modern Legacy

Theia is no longer worshiped, but the things which she represented, sight, light, and wisdom, are still intertwined in Western culture. At least since the scientific revolution, Western culture has focused on sight as the primary sense. It is also used as a metaphor for perception.

One other way in which Theia is referenced in modern culture involves attempts to explain the formation of the moon.

Currently, the most popular hypothesis regarding the origin of the moon is that proto-Earth was impacted by a Mars-sized protoplanet about 4.5 billion years ago. This collision caused both bodies to mostly melt and re-accrete into the Earth-Moon system. Most of this protoplanet merged with proto-Earth, but some of the debris coalesced in Earth’s orbit to eventually become the moon. Appropriately enough, the name given to this hypothetical protoplanet which collided with proto-Earth is Theia.

An artist's rendering of the hypothetical impact of a planet like Theia and Earth. (Public Domain)

An artist's rendering of the hypothetical impact of a planet like Theia and Earth. (Public Domain)

The moon has played an important role in shaping Earth’s surface environment. For example, the gravity of the moon is the main cause of ocean tides. Furthermore, the gravity of the moon has helped to stabilize Earth’s axial tilt (obliquity) over time.

This stabilizing effect causes Earth’s axial tilt to not vary as much over time as it does, say with Mars. This creates relatively stable climatic conditions on Earth which would not be possible without our unusually large moon. We have this large moon all in thanks to Theia which, much like the Theia of Greek mythology, seems to have vanished from the scene but continues to influence the planet through her offspring.

Top image: Theia, Greek goddess of light. Source: gion like/Adobe Stock

By Caleb Strom


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IronicLyricist's picture

I have a deep love of comparative mythology, and greek in specific... Thanks

infinitesimal waveparticles comprise what we call home the earth
manipulatable by thought ability supressed in humans since birth

Caleb Strom's picture


Caleb Strom is currently a graduate student studying planetary science. He considers himself a writer, scientist, and all-around story teller. His interests include planetary geology, astrobiology, paleontology, archaeology, history, space archaeology, and SETI.

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