Up to the early Christian century, Buddhism underwent the phase of metamorphosis. It came to be divided between two major sub-sects- the Lesser Vehicle and the Greater Vehicle. In fact, the greater vehicle or Mahayana subsect originated from Mahasanghikas which got separated from Asthaviravadin sect in the second Buddhist council at Vaishali. Later in the Andhra region (1st B.C.), the new ideas got the fertile land to grow. In Andhra region a separate subsect, Chaityaka emerged. According to this subsect, through the construction of Chaityas and Stupas, one could perform his duties and attain the merits. Gradually it developed into Mahayana ideology. Mahayana Buddhism developed in early 1st century B.C. in Andhra region, although it got formal status after the fourth council at Kashmir.
The cult of Great Vehicle was different in nature from the Lesser Vehicle. Whereas the Lesser Vehicle was giving more emphasis over the historicity of the Buddha, the Great Vehicle gave emphasis over the concept of Bodhisattva. Bodhisattvas were such entities which were having the ability to get Nirvana but they were avoiding his Nirvana for the sake of others. He transferred his merit to others so that they should go on the path of Nirvana. Mahayana Buddhism was having an optimistic approach and it opened the gate of Nirvana for everybody.
In one sense Mahayana Buddhism was the product of new socio-economic conditions. Due to the growth of trade and commerce, there was an emergence of a prosperous mercantile class. The concept of Bodhisattva encouraged Bhaktism and idol worship. The new ideas attracted the mercantile class which gave large donations to Buddhist Monasteries. Even the land grants became a common feature. Mahayana Buddhism came near to Brahmanism. It adopted idol-worship and temple cult (Chaityas). Likewise, it discarded the language of the common people, Pali, and adopted Sanskrit. So in course of time, it was swallowed up by Brahmanism and Buddha was declared to be the tenth reincarnation of Lord Vishnu.