How did the story of the Cowherd and the Weaver Girl evolve?

Look up at the starry sky, have pity on the world, stay sad and don't hate suffering. This is the tenth of nineteen ancient poems, Farewell to the Altair:

Distant Altair, Jiao Jiao Hehan girl.

Skillful hands, make a loom.

There is no chapter all day, and tears are pouring down.

What's the difference between a clear river and a shallow one?

Between water and water, there are no words.

The poem uses the third person to look up at the Altair and Vega on both sides of the Milky Way, and then focuses on describing Vega, shaping her into a beautiful and sad thinking woman, writing the stars in the sky, and metaphorically separating people.

The evolution of the story of the Cowherd and the Weaver Girl can be divided into four periods. Shang and Zhou dynasties are in their infancy. The ancients saw that Tianhe (Hehan, Yinhe) had two bright stars, one of which was called Petunia and the other was called Weaver Girl, like a shuttle weaving. Three thousand years ago, it was clearly recorded in The Book of Songs Xiaoya Dadong that the names of "Weaver Girl" and "Petunia" appeared, but they were written as two, and there was no special relationship between them. The Han Dynasty was a turning point. They began to be dragged from heaven to earth, materialized and personified, and became lovers in love. Take "Far Morning Altar" as an example, Ban Gu's "Xi Du Fu" also said: "Facing Kunming Pool, morning glory on the left, weaver girl on the right, it looks like a vast sea of clouds, and it looks like the Han Dynasty." Wei, Jin, Southern and Northern Dynasties were the shaping period, and they were officially shaped as husband and wife, and Qixi appeared. After the Tang and Song Dynasties, it was a legendary period, decorated with oil and vinegar. Among these four periods, the Han Dynasty is the most crucial, and The Far Altair is undoubtedly an important cultural testimony of the legend of the Cowherd and the Weaver Girl.