This time period was significant in South and Southeast Asian history because of the confluence of different belief practices in the area.
The most recent addition to these was Islam, which most likely was introduced to the region in various simultaneous ways, such as through Arabian, Indian and Chinese trader and scholars. While Islam arrived to these societies, it took a different form than in the Middle East. Instead of impacting political beliefs primarily, its effect was mostly felt in cultural matters.
Another important change that took place in society was the replacement to a large extent of Hinduism by Theravada Buddhism. This allowed for a change in culture towards a more personal, introvert spirituality, as well as an emphasis on individual rituals and effort.
All of these changes resulted in societies that tolerated several religions, and which were syncretic in their practices. Hinduism, Buddhism, Islam and ancient Pan-East Asian Animism all interacted within a single society.