Probably owing to the 2nd century BCE fall of the Mauryan Empire and the subsequent persecutions of Buddhism under Pushyamitra Sunga, it is thought that many Buddhists relocated to the Deccan under the protection of the Andhra dynasty, thus shifting the cave-building effort to western India: an enormous effort at creating religious caves (usually Buddhist or Jain) continued there until the 2nd century CE, culminating with the Karla Caves or the Pandavleni Caves. These caves generally followed an apsidal plan with a stupa in the back for the chaityas, and a rectangular plan with surrounding cells for the viharas.