Timeline of events leading to the American Civil War colonial period in Virginia, slavery had been a part of the socioeconomic system of British North America and was recognized in the Thirteen Colonies at the time of the United States' Declaration of Independence (1776). Since then, events and statements by politicians and others brought forth differences, tensions and divisions between the people of the slave states of the Southern United States and the people of the free states of the Northern United States (including Western states) over the topics of slavery. The large underlying issue from which other issues developed was whether slavery should be retained and even expanded
United States Declaration of Independence against the colonies, "it is necessary that the exercise of every kind of authority under the said crown should be totally suppressed". Adams's preamble was meant to encourage the overthrow of the governments of Pennsylvania and Maryland, which were still under proprietary governance. Congress passed the preamble on May 15 after several days of debate, but four of the middle colonies voted against it, and the Maryland delegation walked out in protest. Adams regarded his May 15 preamble effectively as an American declaration of independence, although a formal declaration would still have to be made. On the same day that