They established a trading settlement in Colombo. By the year 1600, they converted some of the Sinhala royalty to Catholicism, and had a major control over the southwest coastal region.
By then (1604-1635), had established the kingdom of Kandy. His relationship with the Portuguese deteriorated in 1617 & his son also opposed the Portuguese, forming an alliance with the Dutch.
The Dutch alliance also broke down & they captured the eastern ports of the Kandyans.
The Dutch captured the forts, Colombo, Galle & Negombo. By then they had most of the regions of Sri Lanka under their rule. But Kandy maintained their independents.
The first British conquest took place during 1795-1796. They drove the Dutch out of the country & seized all the major ports. The Kandians grip of their own empire were weakening. They managed to beat back the first resistance by the British in 1803.
But eventually the British captured the hill country in 1815. The last of the Sri Lankan Kings were captured & in 1816 he was sent to be imprisoned in Wellor, India.
