The Indus Valley Civilization, which sprawled across the northwest regions of the Indian subcontinent, has been placed by archeologists between 3300 B.C. and 1300 B.C. The planned city of Harappa, a part of Indus Valley, flourished between 2600 B.C. and 1900 B.C. Among the artifacts recovered in the archaeological surveys are the seals which show figures seated in yogic posture. One seal represents a figure seated with extended arms resting on the knees—a classical meditation posture. From these finds it can be inferred that yoga has been practiced in the Indian subcontinent for close to 5000 years. A civilization of the sophistication of the Indus Valley cannot be sustained for more than 2000 years if it was not founded on a strong cultural system—the culture could have been based on the yoga theories and exercises, the Vedic rituals, and the Puranic legends. But most scholars believe that the Vedic civilization came after the decline of the Indus Valley Civilization, between 1500 B.C. and 1200 B.C. The composition of the Rig Veda (the oldest Veda) has been dated between 1300 B.C. and 500 B.C.