Their religion was further developed when they migrated into the Ganges Plain after c. 1100 BCE and became settled farmers, further syncretising with the native cultures of northern India. The Vedic religion of the later Vedic period co-existed with local religions, such as the Yaksha cults, and was itself the product of "a composite of the indo-Aryan and Harappan cultures and civilizations". David Gordon White cites three other mainstream scholars who "have emphatically demonstrated" that Vedic religion is partially derived from the Indus Valley Civilizations.