Southeast Asia
The Jawa Dwipa Hindu kingdom in Java and Sumatra existed around 200 BCE. The history of the Malay-speaking world began with the advent of Indian influence, which dates back to at least the 3rd century BCE. Indian traders came to the archipelago both for its abundant forest and maritime products and to trade with merchants from China, who also discovered the Malay world at an early date. Both Hinduism and Buddhism were well established in the Malay Peninsula by the beginning of the 1st century CE, and from there spread across the archipelago.

Q: Which religions were well established in the Malay peninsula by the beginning of the 1st century CE?
Hinduism and Buddhism