In the year 1713, by the treaty of Utrecht, the _Assiento_, a contract originally entered into by the Spanish government with a company of French merchants for a monopoly by the latter of the trade in slaves to Spanish America, was assigned to the South Sea Company. By the terms of this contract 4,800 negro slaves were to be furnished to the Spanish colonies annually for thirty years, the company being privileged to introduce as many more as could be sold. In this company Queen Anne and the King of Spain became stockholders, as did a large portion of the nobility, gentry, churchmen, and merchants of England. England thus sought a monopoly of the entire slave trade, at least so far as her own and the Spanish colonies were concerned. The exclusive privileges granted to the Royal African Company having expired, in the year 1750 the British Government undertook to maintain the forts and factories on the African coast at its own expense, and the slave trade was thrown open to free competition on the part of its citizens. A great increase of the trade now took place, and England had become the leading nation in that trade, which was carried on chiefly from the ports of Bristol and Liverpool, but other ports including that of London shared in it--the West Indies furnishing the principal market, but a considerable number were also introduced into the colonies of North America. In the meantime the Puritan settlers in New England, under the allurements of the high profits of the trade, had been tempted to engage in it from the time of the earliest settlements there, which they did by evading the monopolies and restrictions in favor of English merchants, and as New England rum was mainly used in the traffic, by the Puritans, the Parliament of Great Britain had, at the instance of English merchants, passed an act, called the "Molasses Act" imposing duties on molasses, sugar and rum imported into the colonies from the French and Dutch West Indies, for the purpose of preventing interference with the English trade in slaves. Numerous acts of the colonial legislatures imposing duties on the importation of slaves, had also been vetoed or repealed by royal proclamation, because they were regarded and styled "impediments to British commerce not to be favoured," and all such acts continued to be vetoed and repealed down to the time of the American Revolution, except in the solitary case of Virginia, when, after repeated acts imposing such duties had been vetoed or repealed, privilege was finally given to the colonial legislature in 1734, to impose a duty to be paid by the colonial _purchaser_ and not the English _seller_.