T he South East region presently shared by Myanmar, Thailand, Cambodia, Laos and Viet Nam is separated from the great Asian continental mass by the series of ranges that run southeast from the Himalayas through Southern China to the sea.
This geographical barrier is crossed by the rivers born in or around the great Tibetan plateau, like the Irrawaddy, the Salween, the Malmen, the Red River and the Mekong, which runs through all the countries of the great Indochina peninsula. Separated by imposing mountain ranges in a North-South direction, these river courses have been since the remotest times the inroads through which successive migratory waves have come to settle down in the fertile plains and in the deltas.
The climate is humid, according to a tropical pattern, with constant temperature and a regime of monsoon rains. The forest vegetation varies following the altitude, which in some peaks reaches 3,000 metres. These geographic and climatic conditions have determined the utilization of the natural resources and the methods of crop growing, and provided the peoples of the region with a great cultural homogeneity, based on fishing and the irrigated cultivation of rice.
South East Asia was for centuries a part in the important maritime trade traffic that ran from Japan to the Mediterranean. This traffic brought with it cultural contributions of India and China. The 16th century witnessed the arrival of Portuguese, Dutch, English and French explorers and traders.