The island was probably originally settled about 1500 years ago by fishermen, but it has only been officially recorded by the Chinese since about 1500 AD, in Ming dynasty maps.
Today Koh Samui belongs to Thailand although because of its long isolation from the rest of the world (little was known about Koh Samui until the early 1970s when it became a stop off on the hippie trail) the islanders still think of themselves as really different from the rest of the country and are proud of their heritage. Samui has a size of about 250Sq KM and is home to around 35,000 people. As everywhere in Thailand, the major religion is Theravada Buddhism and there are lots of simple temples and shrines on the island, sometimes hidden deep in the jungle.
Life on the island is still very quiet, much more so than for instance on Phuket. Koh Samui has not needed to develop industry, and aside for tourism, the main produce of the island are still coconuts and fishing.