In the early 17th century, the Dutch East India Company established a commercial post at Fort Zeelandia (modern-day Anping, Tainan) on a coastal sandbar they called "Tayouan", after their ethnonym for a nearby Taiwanese aboriginal tribe, written by the Dutch and Portuguese variously as Taiouwang, Tayowan, Teijoan, etc. This name was also adopted into the Chinese vernacular (in particular, Hokkien, as Pe̍h-ōe-jī: Tāi-oân/Tâi-oân) as the name of the sandbar and nearby area (Tainan). The modern word "Taiwan" is derived from this usage, which is seen in various forms (大員, 大圓, 大灣, 臺員, 臺圓 and 臺窩灣) in Chinese historical records. The area of modern-day Tainan was the first permanent settlement by Western colonists and Chinese immigrants, grew to be the most important trading centre, and served as the capital of the island until 1887. Use of the current Chinese name (臺灣) was formalized as early as 1684 with the establishment of Taiwan Prefecture. Through its rapid development, the entire Formosan mainland eventually became known as "Taiwan".