The myth of Queen Veerawati is an integral part of the Karva Chauth Katha.
Queen Veeravati was a beautiful princess married to a King. She was also the loving sister of seven brothers who doted on her. On the occasion of the first Karva Chauth, Veeravati went to her father’s house and observed her fast. However, she was a very delicate woman and could not withstand the pressures of fasting without food and water for the whole day and fainted in the evening. The brothers could not bear to see the plight of their sister and so created a reflection through the leaves of a tree which seemed like the moon. Having sighted the moon, Veeravati broke her fast and started to have food.
Just when she began to eat her food, she got the news that her husband, the king had died. She immediately left for her husband’s city. On the way, she met Lord Shiva and Goddess Parvati who told her that her husband had died because she had broken the fast before time and what she had sighted was not the true moon.
On asking for forgiveness and also the fact that it wasn’t actually her fault, Parvati told her that her husband would not die, but would be ill and it would take time before he recovered completely. On reaching the palace Veeravati found her husband unconscious with hundreds of needles in his body. Each day, Veeravati managed to remove one needle from his body and soon enough it was time for the next Karva Chauth, when the king had only one needle in his body.
That year, Veeravati observed her fast very strictly and broke the fast only on sighting the moon. While she was out, the maid who was kept at the kings chambers to keep vigil, removed the lone needle and the king gained consciousness. On gaining conspicuousness, he saw the maid and mistook her to be her queen. When Veeravati came back, she was made to continue as the maid (nobody seems to have any idea why).
Once when the king was going out, he asked Veeravati (who was serving as the maid) if she wanted anything (quite strange, I would think). Veeravati asked for identical dolls, which the king brought for her. On getting the dolls, Veeravati started singing "Roli ki Goli ho gayi... Goli ki Roli ho gayi" (the queen has turned into a maid and the maid has turned into a queen). On asking the reason for such a song, Veeravati told the king the whole story and when the king realised his folly, he gave back Veeravati what was rightfully hers, the status of the queen and wife.
Thus ends the story of a dutiful, obedient, serving wife of the king, which is considered to be the central theme of the festival of Karva Chauth.