In the region between the lower valleys of the Krishna and Godavari which became an important centre of Buddhism at least as early as the 2nd century BC a separate school of art known as Amaravati School flourished. Though it had its beginning in the middle of the 2nd century BC it matured only in the later Satavahana period and declined by the end of the 4th century AD. Its main centres were Amaravati; Nagarjunakonda and Jaggayyapeta.Its artists mainly used white marbel.