There is a legend: Long long ago, there was a poor young man named 牛郎 (literally: cowherd). His only property was a 老牛, and with whom he lived each other. 老牛 was actually a mortal from the haven. He admired and commiserated with 牛郎, so he introduced a heavenly fairy 织女 (literally: weaver girl) to 牛郎. 牛郎 and 织女 soon fell in love, got married, and then had a boy and a girl. The Goddess, 织女’s mother, however, disagreed with their marriage. She forced 织女 to go back haven. This made both 织女 and 牛郎 upset. 老牛 then told 牛郎 to kill him and put on his skin to get the ability to fly to haven. 牛郎 did exactly as what 老牛 told him, and was soon about to reach 织女. At that moment, the Goddess used her hairpin to scratched a wide rive in the sky, and 牛郎 and 织女 were separated again. To help this couple, countless magpie made a 鹊桥 over the river with their bodies. Touched, the Goddess allowed their once-a-year reunion on the evening of the 7th day in the 7th month in lunar calendar. The legend is said to be the origin of the Double Seventh Festival, Altair is said to be the star of 牛郎, with his kids Aquilae β and γ, Vega is said to be the star of 织女, and 银河 is said to be the river.
The Double Seventh Festival is a festival for unmarried girls. On the evening of the Double Seventh Festival, unmarried girls 乞巧, pray for a good skill of waving and sewing, hoping to get a good husband and a happy marriage. On the ceremony of 乞巧, if a girl successfully threads through 七孔针, or her 喜子 (a type of small spider) waves a round web, she is said to get a good skill of waving and sewing.
Chinese poets wrote many poem to describe the story between 牛郎 and 织女, the most well-known among which is 《鹊桥仙》 written by 秦观.