<P> Most of the 17th century slave trade in New England was based in Massachusetts, however, direct attempts were not successful until the latter half of the century . In 1676, Boston ships began working with slave traders in Madagascar and by 1678 were selling slaves to Virginians . As for slaves imported to Massachusetts, operators preferred to trade Africans for more experienced slaves in the West Indies . Some Africans unsuitable for work in the West Indies were also brought to Massachusetts for sale . Boston ships were selling slaves to Connecticut by 1680 and Rhode Island by 1696 . </P> <P> The slave population in Massachusetts was under 200 in 1676, 550 in 1708 and 2,000 by 1715 . Slaves accounted for 2.2% of the total population from 1755 to 1764, their highest rate . There was a larger free black population, with about 10% of the population of Boston being black in 1752 . </P> <P> By the mid-18th century, enslavement of Africans had become common practice in Massachusetts . A 1754 census listed nearly 4500 slaves in the colony . Abolitionist sentiment had been growing, especially as the philosophical underpinnings of independence and democracy became common parlance in the colony . While Massachusetts had derived wealth from the Triangle Trade, its merchant and mixed economy was not dependent on slave labor to the extent of southern states . </P> <P> There were three trials related to these events, two civil and one criminal . These took place during the American Revolutionary War, when language about the equality of people was in the air and after the new Massachusetts constitution had been passed in 1780 . The civil cases were: Jennison v. Caldwell (for "deprivation of the benefit of his servant, Walker"), apparently heard and decided first, and Quock Walker v. Jennison (for assault and battery), both heard by the Worcester County Court of Common Pleas on June 12, 1781 . </P>

When was slavery officially encoded into massachusetts colonial law