In 1637 the Portuguese-owned region of Cearà or Siara, situated to the north of Pernambuco, was conquered by the Dutch West-India Company (WIC) without much resistance. Indigenous tribes had requested Dutch help in their fight against the Portuguese in the region, who grew sugar cane there. For the WIC, the area proved to be more attractive for winning salt than for growing sugar cane. When the Dutch conquered the region in 1637, the Portuguese fort Siara had been there for quite a few years. The Dutch abandoned Siara by the end of 1643. An epidemic of smallpox and the forced labour led the indigenous population to revolt against the Dutch. The Dutch population in Siara was entirely wiped out. In April 1649, Siara was retaken by the WIC. A new fort was erected, named Fort Schoonenburgh. The WIC's main interest there was in the silver mines in the vicinity. Siara was subsequently ceded to Portugal as part of the Dutch surrender of their Brazilian territories in 1654.