Amarasi was a traditional princedom in West Timor, in present-day Indonesia. It had an important role in the political history of Timor during the 17th and 18th century, being a client state of the Portuguese colonialists, and later subjected to the Netherlands East Indies.
The origins of Amarasi are recounted in various legends. The oldest available version says that the dynastic line originated from Wehali, the traditional political navel of Timor in Belu. A member of a local family, Nafi Rasi, accidentally broke a valuable bowl and was forced too flee the wrath of his siblings. With his followers he went to Beboki-Insana to the north of Wehali, and thence to the south coast of West Timor.
There he founded a princedom with help of firearms that he had acquired in Beboki-Insana, which in turn lay close to the land of the Topasses (Portuguese mestizo population). Roaming groups from Belu arrived and strengthened the manpower of Nafi Rasi. In spite of its supposed Belunese origins, the population belonged to the Atoni group, speaking a dialect of Dawan.
European sources confirm that Amarasi was a powerful domain in western Timor by the early 17th century. It was influenced by Catholicism through Dominican missionaries in the 1630s, and turned an important client of the Portuguese Topasses. In consequence, Amarasi fought the Dutch East Indies Company (Vereenigde Oost-Indische Compagnie or VOC), which attempted to expand its power on Timor, attracted by the stands of commercially valuable sandalwood. A sizeable Dutch expedition led by Arnold de Vlaming van Oudshoorn (1656) was soundly defeated by Amarasi and the Topasses.