The Gandhara civilization emerged in the 6th century BCE in the region of northern Pakistan and eastern Afghanistan. It reached its peak under the Kushan Empire from the 1st to 5th century CE. Buddhism was the dominant religion and spread from Gandhara as far as Japan and Korea. The civilization declined due to the loss of popularity of Buddhism and invasions of the Huns and other tribes in the 5th-6th centuries CE, disrupting trade and urban centers.