Before the charters were surrendered, however, settlements had been started in both territories. In Virginia, the province of the London Company, the first shipload of adventurers from London arrived in the year 1607. But twelve years of hard and painful struggle were required to establish this settlement as a permanent and self-maintaining colony. It is interesting to note that at this time, and in this place, one of the greatest of our national racial problems had its commencement, through the introduction of a number of African slaves from a Dutch vessel in 1619. The settlers in this region were, in part, adventurers, younger sons of noble families, and other members of the aristocracy who found it advisable to leave England, and in part rather unworthy representatives of the lower classes. A combination of political, social, and economic causes was responsible for their coming. The settlers of the northern colony, in the territory of the Plymouth Company, were of a different class of the population. Their motives for coming were also different, being primarily of a religious character. These colonists were separatists from the Church of England, who fled first to Holland, and from there came to America in 1620, landing in what is now Plymouth, Massachusetts. In this colony, also, the process of settlement was slow, and there were very few arrivals for ten years. In 1630, however, about one thousand colonists, Puritans but not separatists, came over, and settled in Massachusetts Bay. This was the real beginning of the history of the Massachusetts colony, which in time absorbed also the Plymouth colony. Once started, population in this colony advanced very rapidly, and overflowed into the neighboring regions, forming the colonies of Rhode Island, New Hampshire, and the river towns of Connecticut. In the meantime the Dutch were taking possession of the unassigned central region. New Netherland was organized under the Dutch West India Company in 1621, and the city at the mouth of the Hudson was named New Amsterdam. Sweden, too, was trying to get a foothold in the new country and sent a party of colonists to Delaware Bay in 1638. This was not successful, however, and surrendered to the Dutch in 1655, so that Sweden never achieved prominence as a colonizing power in the New World. With the growth of the English colonies in the north and south, this central territory in the hands of a foreign power came to be recognized as a source of annoyance and danger, and on the occasion of a war with Holland, England sent over a fleet and took possession of the whole intervening region, forming the colonies of New York and New Jersey. In 1681 the territory of Pennsylvania was granted for settlement to William Penn, and thus the whole Atlantic coast from Canada to Florida became a field of colonization, subject to the English authority.