 The union of lingam and yoni represents the "indivisible two-in-oneness of male and female, the passive space and active time from which all life originates".A complementary theory suggests that the Lingam represents the beginning and ending "Stambha" pillar symbolizing the infinite nature of Shiva.The propagation of "linga" worship on a large scale in South India is believed to be from Chola times (late 7th century A.D.), through "Rig veda", the oldest literature details about worshipping Shiva in the form of "linga".