This personal union can hardly be called part of the expansion of England, but it had been prepared by some assimilation and cooperation between the two peoples, and it was followed by a great deal more. The plantation of Ulster by English and Scots after the flight of the Irish earls of Tyrone and Tyrconnell in 1607 is one illustration, and Nova Scotia is another; but Virginia, the first colony of the empire, was a purely English enterprise, and it cradled the first-born child of the Mother of Parliaments. To Virginia men went for profit; principle drove them to New England. The Pilgrim Fathers, who sailed in the _Mayflower_ in 1620, had separated from the church and meant to separate from the state, and to set up a polity the antithesis of that of Laud and the Stuarts. But there was something in common between them; the Puritans, too, wanted uniformity, and believed in their right to compel all to think, or at least to worship, alike. Schism, however, appeals with ill grace and little success to authority; and dissentients from the dissenters formed Independent offshoots from New England. But all these Puritan communities in the north were different in character from Virginia in the south; they consisted of democratic townships, Virginia of plantations worked by slaves. Slave labour was also the economic basis of the colonies established on various West Indian islands during the first half of the seventeenth century; and this distinction between colonies used for exploitation and colonies used for settlement has led to important constitutional variations in the empire. Only those colonies in which large white communities are settled have received self-government; those in which a few whites exploit a large coloured population remain subject to the control of the home government. The same economic and social differences were responsible for the great American civil war between North and South in the nineteenth century.