How did Portugal gain control of trade in Southeast Asia?
They used military force.
southeast asia consists of 12 countries and they are the trade routes between south asia, east asia , Africa and Europe. during colonial times, it was a trade route for eurpean colonizers to exploit oil , timbers, and spices from india. singaphore's economy was based on the trade ports and all of the imports such as technologies and automobiles from europe and west are intercepted by singaphore and transported them to south asia.
Europeans wanted southeast Asian countries because of their location along the sea route to China. Europeans also recognized the value of the Pacific colonies as sources of tropical agriculture, minerals, and oil. Also, the Europeans knew that Southeast Asia held a rapidly growing spice trade which earned significant money. Europe also wanted technology, and control of other countries.