said that in pre-Protectorate days there was a "Grand Poro" with cross-chiefdom powers of making war and peace. It is widely agreed that it has a restraining influence on the powers of the chiefs. Headed by a fearsome principal spirit, the Gbeni, it plays a major role in the rite of passage of males from puberty to manhood. It imparts some education. In some areas, it had supervisory powers over trade, and the banking system, which used iron bars as a medium of exchange. It is not the only important society in Sierra Leone: the Sande is a female-only analogue of it; there is also the Humoi which regulates sex, and the Njayei and the Wunde. The Kpa is a healing-arts collegium. The impact of the Mane invasions on the Sapes was obviously considerable, in that they lost their political autonomy. There were other effects as well: trade with the interior was interrupted, and thousands were sold as slaves to the Europeans. In industry, a flourishing tradition in fine ivory carving was ended; however, improved ironworking techniques were introduced. 1600–1787 By the 17th century, Portuguese colonialism in West Africa began to wane, and in Sierra Leone other European colonial powers such as the English and Dutch began to supplant their influence in the region. In 1628, a group of English merchants had established a factory in the vicinity of Sherbro Island, about 50 km (30 mi) south-east from present-day Freetown. In addition to ivory and slaves, the merchants at the factory also traded in camwood, a type of hard timber. The Portuguese missionary Baltasar Barreira ministered in Sierra Leone until 1610. Jesuits, and later in the century, Capuchins, continued the mission. By 1700 it had closed, although priests occasionally visited. In 1663, the Royal African Company (RAC) was granted a royal charter from Charles II of England and soon established a factory on Sherbro Island and Tasso Island. During the Second Anglo-Dutch War, both factories were sacked by a Dutch Navy force in 1664. The factory was rebuilt, though it was sacked again by the French Navy during the War of the Spanish Succession in 1704 and pirates in 1719 and 1720. After the Dutch raid on the RAC factory at Tasso Island, it was relocated to the nearby Bunce Island, which was more defensible. The Europeans made payments, called Cole, for rent, tribute, and trading rights, to the king