Buddhism in the Indian state of Himachal Pradesh has been a long recorded practice. The spread of Buddhism in the region has occurred intermediately throughout its history. Starting in the 3rd century BCE, Buddhism was propagated by the Maurya Empire under the reign of Ashoka. The region would remain an important center for Buddhism under the Kushan Empire and its vassals. Over the centuries the following of Buddhism has greatly fluctuated. Yet by experiencing revivals and migrations, Buddhism continued to be rooted in the region, particularly in the Lahaul, Spiti and Kinnaur valleys.