Historical records indicate that the people who live in island Southeast Asia today migrated there from the mainland of Asia. They passed through the Indo-China Peninsula and Malay Peninsula, then reached Indonesia and the Philippine Archipelago. This wave of immigration brought the primary techniques of fishing and growing rice. Indian and some Chinese administrative concepts were adopted in the area in the fourth to fifth century. At first India influenced this area through the spread of Hinduism, then later through Buddhism. During this period, religion became the most important element in the lives of the region's inhabitants. Missionaries and traders had already started to arrive in the region in the 18th century and the early 19th century, before the imposition of colonial rule; their presence caused many changes in the region.