At some point during the Bronze Age (starting in the 4th millennium BCE) the original Goddess myth started to change.
While during the Neolithic (~ 6,500 to 3,500 BCE) the Goddess was understood to be immanent and androgynous with both the womb and the entire generative life force seen as being a part of Her, during the Bronze Age Her essence was split into the permanent female principle – the Goddess – and the forever changing o principle – Her Son-Lover or Consort.  The main story themed around the Goddess giving birth to a son, who would then become Her lover and essentially father himself. While the Goddess remained constant and immortal, Her Son-Lover would ultimately face death and enter the underworld. As a major part of the myth the Goddess would then go after him to resurrect him.
The myth of the Goddess and Her Son-Consort represented both the Wheel of the Year, whereby the Goddess was everlasting nature and her Son-Lover the ever-growing, ever-dying vegetation, as well as the moon’s cycles, whereby the Goddess was the Moon as a whole and her Son-Lover the ever-changing phases of the Moon.
At the same time as the split between nature / life as a whole (the Goddess) and its temporary manifestations as human, animal and plant life (the Son-Lover-Consort) took place, the Goddess became associated with the planet we call Venus. 
The planet Venus was seen as being the Daughter of the Moon and each of the Venus Goddesses all still clearly showed their neolithic roots as Moon Goddesses.
The Venus Goddesses include Inanna in Sumer, Ishtar in Babylon, Astarte in Canaan, Isis in Egypt, Aphrodite in Greece, Venus in Rome and, in a way, Freya in Scandinavia / Northern Germany. 
Unlike the Goddess as the Moon with Her three aspects – the Maiden, the Mother and the Crone – the Goddess as Venus was generally seen as an all-in-one Goddess. She was the Goddess of Heaven, Earth and the Underworld, She was the Life Giver and Death Bringer, She was the Goddess of Love and Fertility, as well as Destruction and Death. She was the Ruler of the Underworld where the dead would reside until their subsequent rebirth. The Goddess as Venus was a Goddess of Time, Fate, Natural Order and Harmony.
The planet Venus is acually quite similar to the Moon. Due to her being an inner planet (the same as Mercury), from our vantage point Venus appears, disappears and then later reappears over a period of about 18 months.
After the Sun and the Moon Venus is the brightest body visible in the sky. She is either a Morning Star or an Evening Star. The Greeks would call Venus Phospheros (= Bringer of Light) when she appeared just before dawn and Hesperos (= the western one) when she appeared in the evening. The Roman equivalents were Lucifer (= the light bringer) and Vesper (= evening), respectively. 
Just before Venus appears in the eastern sky as a Morning Star, she disappears from our sight for 14 days, after which she reappears in the east where she rises daily for about 8 to 9 months. She then disappears again for about 3 months this time only to reappear in the west just before sunset, where she remains for another 8 months. After that the cycle stars again.
When drawn graphically the movement of Venus relative to the Sun and the Earth traces out a 5-pointed star or a pentacle. For that reason the Goddess is often associated with the 5-pointed star. Inanna, on the other hand, is associated with Venus as an 8-pointed star or rosette. This most likely refers to the planet’s 8-year pentacle cycle, i.e. the length of time it takes for Venus to wander across the sky in an apparent pentacle shape, and / or her 8-month period as a Morning or Evening Star. Venus’s maximum elongation from the Sun is between 45º and 47º. When drawn out grahically within a circle this traces an 8-pointed star.
In her book A Magical Tour of the Night Sky Reena Shesso explains a possible link between the relationship between Venus and the Moon in the sky and the Venus Goddess and Her Son-Lover in Near Eastern mythology.
When Venus is an Evening Star she only meets the Moon in her waxing crescent phase. Shesso uses the Goddess Inanna and Her Consort Dumuzi to elaborate the example. Inanna is Venus while Dumuzi, the “wild bull”, is the waxing crescent Moon. However, with the Moon and Dumuzi ultimately being manifestations of the Goddess Herself, the Moon in the story also represents Inanna’s lap and Her Boat of Heaven. As the Moon grows bigger every day and spends more and more time with Venus in the evening sky, so do Inanna and Dumuzi become more and more enamoured with each other and spend more and more time making love. The ancient Sumerian poems talk about Inanna’s lap being “filled with milk and cream” which is a double metaphor for, of course, on the one hand Inanna and Dumuzi’s lovemaking and on the other hand the growing crescent moon. In some years Inanna-Venus and Dumuzi-Moon come so close to each other that the Moon eclipses Venus.
Eventually Inanna enters into the Underworld and Venus disappears from our skies. While Inanna is gone, Dumuzi shines brightly as the full moon. Eventually Inanna resurfaces and Venus reappears in the eastern sky as a Morning Star. Now Inanna-Venus and Dumuzi-Moon only meet when the latter is feeling weakened and remorseful and is on his way into the Underworld in Inanna’s stead. In the sky when Venus is a Morning Star the Moon is in her waning phase going in the opposite direction whenever the two meet. Eventually the Moon disappears for three days completely while Venus continues to shine brightly every morning. The myth may very well be expressing these natural events pictorially when Inanna is angered by Dumuzi’s gloating during Her stay in the Underworld and She therefore chooses him to be Her replacement in the Realm of the Dead.
Variants of the same myth can be found all over the Ancient Near East, Classical Greece and even Christianity. They essentially all centre around the Wheel of the Year and the recurrent Death and Renewal of the Vegetation God. In addition, those stories also try to explain our own Cycle of Life, where each individual, personal soul (Son-Lover-Consort, Greek “bios”, Egyptian “Ba”) separates from the immortal, universal soul or life force (the Goddess, Greek “zoe”, Egyptian “Ka”) to live her / his own unique life until physical death reunites them with the universal life-force, the Goddess.
Over time, as the centuries and millennia went by, life changed for the Bronze Age people and so did their interpretation of the Venus Goddess and Her Son-Lover-Consort. Invasions and wars became more prevalent and villagers were forced to congragate in reinforced towns, cities and eventually city-states. While at first the Son-Lover was only seen as a representative of the temporary aspect of nature, over time his importance and power grew until he became equal to his Mother. Eventually, of course, he would supersede Her and become Her father. Back in the Bronze Age the human ruler of the land identified himself with the Son-Lover-Consort of the Venus Goddess. At first he literally was seen as the human representative of the vegetation god that would die and be reborn every so often (usually every 8 years, one Venus pentagram cycle). His earthly reign was only possible through the Sacred Marriage with the Goddess (or Her priestess representative). As time went on and the Consort grew in importance, so did his representative, the king.
By the end of the Bronze Age the Goddess no longer reigned supreme, but according to later myths She now willingly did the god’s and thus the king’s bidding. As a result the Venus Goddess had become, on the one hand, the Goddess of Love and Fertility, and on the other, the Goddess of Battle and War. Often the role of Goddess of the Underworld would be passed on to either Her sister or a male god. However, even at the end of the Bronze Age, as late as 1,500 BCE, the Goddess as Venus was still a Goddess over Life and Fertility as well as Death and Battle, and in case of Isis, so much more still. The Bronze Age Venus Goddess was still much more than would eventually be attributed to Her, that of being merely a Goddess of Love and Beauty.
The original Venus Goddess in Her aspect of Shaman who travels through the underworld is Mercury, the planet of magic and communication.
The original Venus Goddess in Her loving, nurturing aspect is Venus, the planet of love, art and beauty.
The original Venus Goddess in Her aspect of passionate Creatrix-Destructress is Mars, the planet of strength, courage and drive.
 This supports the assertion that even at least during the early Bronze Age family life was matrilocal, which means that women always stayed home with their mothers, sisters, daughters and young sons, whereas men relocated to live with their “wife”‘s family. In some cases the men also stayed at their own mother’s house and acted as fathers to their neices and nephews instead of their own children.
 The Venus Goddess was usually also associated with the star Sirius in the constellation of Canis Major, also known as the “dog star”. In Egypt where the Goddess Isis was linked to Sirius, the star was known as Sothis.
 Freya has never been expressly linked to the planet Venus, but she has by association. Freya was a shaman or witch and Venus as the Evening Star was linked to witches or wise-women.
 Interesting that the Latin “Lucifer”, the Light Bringer, has become synonymous with the devil.