The motivations of slave owners in manumitting slaves were complex and varied. Firstly, manumission may present itself as a sentimental and benevolent gesture. One typical scenario was the freeing in the master's will of a devoted servant after long years of service. A trusted bailiff might be manumitted as a gesture of gratitude; for those working as agricultural laborers or in workshops, there was little likelihood of being so noticed.
Such feelings of benevolence may have been of value to slave owners themselves as it allowed them to focus on a 'humane component' in the human traffic of slavery. In general, it was more common for older slaves to be given freedom, once they had reached the age where they were beginning to be less useful. Legislation under the early Roman empire put limits on the number of slaves that could be freed in wills (Fufio-Caninian law 2 BC), which suggests that it had been widely used.
Freeing slaves could serve the pragmatic interests of the owner. The prospect of manumission worked as an incentive for slaves to be industrious and compliant. Roman slaves were paid a wage (pecunium) with which they could save up to, in effect, buy themselves. Manumission contracts found in some abundance at Delphi specify in detail the prerequisites for liberation.
Greek slaves were generally not permitted to become citizens on being manumitted, being merely allowed to remain as resident aliens. Even in freedom, the ex-slave could be bound to some continuing duty to the master and were commonly required to live nearby the former master (paramone). Breaches of these conditions could lead to beatings, prosecution at law and re-enslavement. Sometimes extra payments were specified by which a freed slave could liberate himself from these residual duties. But ex-slaves were able to own property outright, and their children were free of all constraint.
Under Roman law, a slave had no personhood and was protected under law mainly as his or her master's property. In ancient Rome, a slave who had been manumitted was a libertus (feminine liberta) and a citizen.
A freed slave customarily took his or her former owner's family name, that is, the nomen (see Roman naming conventions) of his or her master's gens. The former owner became his or her patron (patronus). As a client (cliens), the freed person retained certain obligations to his or her master, who in turn owed mutual favors. A freed slave could also acquire multiple patrons.
A freed slave became a citizen. Not all citizens, however, held the same rights and privileges (for instance, women were citizens, but could not vote or hold public office; see Roman citizenship). The former slave's rights were limited or defined by particular statutes. Freed slaves could become civil servants but not hold the higher magistracies (see for instance apparitor and scriba), priests of the emperor, and hold other highly respected public positions. If they were sharp businesspeople, there were no social limits to the wealth they could amass. The children of a freedman held full legal rights, though Roman society was stratified. One of the most famous Romans to have been the son of a freedman was the poet Horace, who enjoyed the patronage of Augustus.
African slaves were freed in the North American colonies as early as the seventeenth century. Some (such as Anthony Johnson) went on to become landowners and slaveholders in the colonies. Slaves could sometimes arrange manumission by agreeing to "purchase themselves"; that is, to pay the master an agreed amount. Some masters demanded market rates; others set a lower amount in consideration of service.
Regulation of manumission began in 1692, when Virginia established that in order to manumit a slave, a person must pay the cost for them to be transported out of the colony. A 1723 law stated that slaves may not "be set free upon any pretence whatsoever, except for some meritorious services to be adjudged and allowed by the governor and council." In some cases, when a master was drafted into the army, they sent a slave in their place, with a promise of freedom if they survived the war. The new government of Virginia repealed these laws in 1782 and declared freedom for slaves who had fought for the Colonies in the American Revolutionary War. The 1782 laws also permitted masters to free their slaves on their own accord; previously, a manumission required obtaining consent from the state legislature, an arduous and rarely granted request. However, as population of free negroes increased, the state passed laws forbidding free negroes from moving into the state (1778) and requiring newly freed slaves to leave within one year unless they had special permission (1806).
Various other states at this time established laws governing manumission and tended to make it easier to accomplish. In the first two decades after the American Revolution, many of the new states passed laws allowing slaveholders to declare slaves free by filing papers, and numerous manumissions were made in the idealism of the war. The percentage of free blacks as a proportion of the total black population increased in the Upper South from less than 1 percent to nearly 10 percent in this period. In Virginia, the proportion of free blacks increased from 1% in 1782 to 7% in 1800. Together with several northern states abolishing slavery during this period, the percentage of free blacks nationally increased to 13.5 percent of the total black population.
After invention of the cotton gin in 1793, which enabled the development of extensive new areas for new types of cotton cultivation, manumissions decreased due to increased demand for slave labor. In the nineteenth century, slave revolts such as the Haitian Revolution and especially the 1831 rebellion led by Nat Turner increased slaveholder fears, and most southern states passed laws making manumission nearly impossible until the passage of the Thirteenth Amendment to the United States Constitution, which abolished slavery, except as a punishment for crime whereof the party shall have been duly convicted, after the American Civil War in 1865.
In the Upper South in the late eighteenth century, planters had less need for slaves as they switched from labor-intensive tobacco cultivation to mixed-crop farming. Slave states such as Virginia made it easier for slaveholders to free their slaves. In the two decades following the American Revolutionary War, numerous slaveholders accomplished manumissions by deed or in wills, so that the percentage of free blacks to the total number of blacks rose from less than one percent to 10 percent in the Upper South. Some northern states quickly abolished slavery, adding to the national population of free blacks; New York and New Jersey adopted gradual abolition laws that kept the free children of slaves as indentured servants into their twenties.
Of the Founding Fathers of the United States as defined by the historian Richard B. Morris, the southerners were the major slaveholders, but northerners also held them, in generally fewer number, as domestic servants. John Adams owned none; George Washington freed his slaves in his will (his wife independently held numerous dower slaves); Thomas Jefferson freed five slaves in his will, and the remaining 130 were sold to settle his estate debts; James Madison did not free his slaves and some were sold to pay off estate debts, and his wife and son retained most to work Montpelier plantation; Benjamin Franklin freed his slaves; Alexander Hamilton likely owned slaves and freed them, as he was an officer of the New York Manumission Society; the society was founded by John Jay, who freed his domestic slaves in 1798, the same year as governor he signed a gradual abolition law in New York; John Dickinson freed his slaves in a manumission process between 1776 and 1786, the only Founding Father to do so during this time.
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