When the Underworld god Hades abducted the young maiden Persephone, her mother, Demeter, wouldn't feed the world, and so, winter came upon the land. When Persephone was restored, an elated Demeter gave the gift of agriculture to mankind.
The goddess Demeter was called Thesmophoros because she gave certain thesmoi 'laws' to mankind, and the holiday of Themophoria honors her. Learn more about the unusual customs of the ancient Greek fall festival known as Thesmophoria.
See

• Thesmophoria - Greek Thanksgiving
  
• In Aristophanes' comedy, The Thesmophoriazusae, a man tries to infiltrate the all-women rites of the Thesmophoria holiday.
  
• Persephone
  
• Demeter
  

Image of Demeter and Persephone © Clipart.com