Gabriel's Rebellion was a planned
slave rebellion
A slave rebellion is an armed uprising by enslaved people, as a way of fighting for their freedom. Rebellions of enslaved people have occurred in nearly all societies that practice slavery or have practiced slavery in the past. A desire for freedo ...
in the
Richmond, Virginia
(Thus do we reach the stars)
, image_map =
, mapsize = 250 px
, map_caption = Location within Virginia
, pushpin_map = Virginia#USA
, pushpin_label = Richmond
, pushpin_m ...
, area in the summer of 1800. Information regarding the revolt, which came to be known as "Gabriel's Rebellion", was leaked prior to its execution, and Gabriel, a blacksmith who planned the event, and twenty-five followers were
hanged
Hanging is the suspension of a person by a noose or ligature around the neck.Oxford English Dictionary, 2nd ed. Hanging as method of execution is unknown, as method of suicide from 1325. The ''Oxford English Dictionary'' states that hanging in ...
. The site of Gabriel's execution was for several years believed to have been at the
Shockoe Bottom African Burial Ground, historically known as the Burial Ground for Negroes. His execution was advertised as occurring at the usual place, however in 1800 that may have been a location other than the Burial Ground for Negroes. The location of Gabriel's burial is also unknown.
Gabriel's planned uprising was notable not because of its results—the rebellion was quelled before it could begin—but because of its potential for mass chaos and widespread violence. There were other slave rebellions, but this one "most directly confronted" the
Founding Fathers
The following list of national founding figures is a record, by country, of people who were credited with establishing a state. National founders are typically those who played an influential role in setting up the systems of governance, (i.e. ...
"with the chasm between the ideal of liberty and their messy accommodations to slavery."
Virginia and other state legislatures passed restrictions on
free blacks, as well as prohibiting the education, assembly, and hiring out of slaves, to restrict their ability and chances to plan similar rebellions.
In 2002, the
City of Richmond
The City of Richmond was a local government area about east of Melbourne, the state capital of Victoria, Australia. The city covered an area of , and existed from 1855 until 1994.
History
Richmond was incorporated as a municipality on 24 Ap ...
passed a resolution in honor of Gabriel on the 202nd anniversary of the planned rebellion. In 2007, Governor
Tim Kaine
Timothy Michael Kaine (; born February 26, 1958) is an American lawyer and politician serving as the junior United States senator from Virginia since 2013. A member of the Democratic Party, he served as the 38th lieutenant governor of Virgini ...
gave Gabriel and his followers an informal pardon, in recognition that his cause, "the end of slavery and the furtherance of equality for all people—has prevailed in the light of history".
Gabriel Prosser
![Blacksmith Historic Westville](https://upload.wikimedia.org/wikipedia/commons/4/4b/Blacksmith_Historic_Westville.jpg)
Gabriel ( – October 10, 1800), referred to by some as Gabriel Prosser, the surname of his slaveholder,
was a man of African descent born into slavery in 1776 at
Brookfield, a large tobacco plantation in
Henrico County, Virginia
Henrico County , officially the County of Henrico, is located in the Commonwealth of Virginia in the United States. As of the 2020 census, the population was 334,389 making it the fifth-most populous county in Virginia. Henrico County is incl ...
.
He and two brothers, Solomon and Martin, were held in bondage by slaveholder
Thomas Prosser, the owner of Brookfield. Gabriel was literate.
He was one of the rare 5% of enslaved people of the colonial era who were able to learn to read and write.
Gabriel trained as a
blacksmith
A blacksmith is a metalsmith who creates objects primarily from wrought iron or steel, but sometimes from #Other metals, other metals, by forging the metal, using tools to hammer, bend, and cut (cf. tinsmith). Blacksmiths produce objects such ...
and a carpenter.
His brother Solomon, and perhaps his father, was a blacksmith.
Gabriel, "hired out" by his enslaver to work in Richmond foundries,
was able to keep a portion of the wages that he earned. The bulk of it went to Thomas Prosser.
Gabriel traveled freely throughout Richmond and Henrico County to work for plantation and business owners.
Gabriel was married to Nanny, an enslaved woman. They were not known to most historians as having had any children.
He was described in newspaper articles as having stood "six feet two or three inches high". His long and "bony face, well made", was marred by the loss of his two front teeth and "two or three scars on his head".
White people as well as black people regarded the literate young man as "a fellow of great courage and intellect above his rank in life".
In 1799, Gabriel, his brother Soloman, and a man named Jupiter, tried to steal a pig from Absalom Johnson. Gabriel got into a scuffle with Johnson and he bit off part of Johnson's ear.
Jupiter was charged with stealing a hog, which was a misdemeanor and Soloman was not charged. It was a capital offense for an enslaved person to assault a white person. He could have been hanged for the assault. Because he was a valuable bondsman for Prosser, the judge sentenced him to jail for one month and had his thumb branded.
Gabriel was released from jail when slaveholder Prosser paid a bond for his release and he promised a year of good behavior. Richmond history professor and slave law expert Philip J. Schwarz states that it showed Gabriel's intention "to consciously challenge the system of slave control."
''See also
History of slavery in Virginia § Food.''
Historian Douglas R. Egerton and author of ''Gabriel's Rebellion,'' states: "He was physically big, he was literate, he's a fighter, he's a skilled artisan. For all these reasons, he was a natural leader."
Background to the revolt
In Richmond, there were slightly more blacks than whites, with a total population of 5,700 in 1800. Richmond was a slave town, with a community whipping post where slaveholders had punishment meted out in a public square. Enslaved men loaded and moved flatboats of tobacco and other cargo. Throughout the state in 1800, 39.2% of the total population were slaves; they were concentrated on plantations in the
Tidewater region
Tidewater refers to the north Atlantic coastal plain region of the United States of America.
Definition
Culturally, the Tidewater region usually includes the low-lying plains of southeast Virginia, northeastern North Carolina, southern Maryl ...
and west of Richmond.
Gabriel, living in Virginia in the late eighteenth century, was influenced by the prevailing themes of liberty expounded by the supporters of the
American
American(s) may refer to:
* American, something of, from, or related to the United States of America, commonly known as the "United States" or "America"
** Americans, citizens and nationals of the United States of America
** American ancestry, pe ...
.
During his lifetime, the number of
free people of color
In the context of the history of slavery in the Americas, free people of color (French: ''gens de couleur libres''; Spanish: ''gente de color libre'') were primarily people of mixed African, European, and Native American descent who were not ...
had grown markedly in the
Upper South
The Upland South and Upper South are two overlapping cultural and geographic subregions in the inland part of the Southern and lower Midwestern United States. They differ from the Deep South and Atlantic coastal plain by terrain, history, econom ...
. Many slaves were
manumitted
Manumission, or enfranchisement, is the act of freeing enslaved people by their enslavers. Different approaches to manumission were developed, each specific to the time and place of a particular society. Historian Verene Shepherd states that t ...
thanks in part to the efforts of
Methodist
Methodism, also called the Methodist movement, is a group of historically related denominations of Protestant Christianity whose origins, doctrine and practice derive from the life and teachings of John Wesley. George Whitefield and John's b ...
and
Quaker
Quakers are people who belong to a historically Protestant Christian set of Christian denomination, denominations known formally as the Religious Society of Friends. Members of these movements ("theFriends") are generally united by a belie ...
abolitionists.
Their number was augmented by free black refugees from the
Haitian Revolution
The Haitian Revolution (french: révolution haïtienne ; ht, revolisyon ayisyen) was a successful insurrection by slave revolt, self-liberated slaves against French colonial rule in Saint-Domingue, now the sovereign state of Haiti. The revolt ...
, many of whom had been slaveowners themselves.
Some Virginia slaveholders were nervous about the sharp increase in the number of free blacks in the slave state.
The revolt and outcome
Some historians assert that Gabriel became the leader of the planned rebellion because he was highly intelligent, literate, and a blacksmith. Enslaved and free Black-American men in Virginia taught their metalwork skills to their sons.
During the spring and summer of 1800, Gabriel began to plan a revolt that intended to end slavery in Virginia.
Plans were made with enslaved people over 10 counties and the cities of
Richmond
Richmond most often refers to:
* Richmond, Virginia, the capital of Virginia, United States
* Richmond, London, a part of London
* Richmond, North Yorkshire, a town in England
* Richmond, British Columbia, a city in Canada
* Richmond, California, ...
,
Norfolk
Norfolk () is a ceremonial and non-metropolitan county in East Anglia in England. It borders Lincolnshire to the north-west, Cambridgeshire to the west and south-west, and Suffolk to the south. Its northern and eastern boundaries are the No ...
, and
Petersburg, Virginia
Petersburg is an independent city in the Commonwealth of Virginia in the United States. As of the 2020 census, the population was 33,458. The Bureau of Economic Analysis combines Petersburg (along with the city of Colonial Heights) with Din ...
.
He and his brothers, as well as other blacksmiths, turned scythe blades into as many as twelve dozen swords. Musket balls and 50 spears were created. They intended to steal muskets from a tavern.
Hundreds of slaves from central Virginia expected to march into Richmond and take control of the
Virginia State Armory and the
Virginia State Capitol
The Virginia State Capitol is the seat of state government of the Commonwealth of Virginia, located in Richmond, the third capital city of the U.S. state of Virginia. (The first two were Jamestown and Williamsburg.) It houses the oldest elected ...
. The plan was to hold Virginia's Governor
James Monroe
James Monroe ( ; April 28, 1758July 4, 1831) was an American statesman, lawyer, diplomat, and Founding Father who served as the fifth president of the United States from 1817 to 1825. A member of the Democratic-Republican Party, Monroe was ...
hostage so that they could negotiate for their freedom.
But on August 30, 1800, the planned day of attack, heavy rain flooded the streets of Richmond and the creeks in central Virginia.
In addition, two slaves told their owner, Mosby Sheppard, about the plans. Sheppard warned Governor Monroe, who called out the state
militia
A militia () is generally an army or some other fighting organization of non-professional soldiers, citizens of a country, or subjects of a state, who may perform military service during a time of need, as opposed to a professional force of r ...
. They patrolled the area and began picking up conspirators.
Gabriel escaped downriver to
Norfolk
Norfolk () is a ceremonial and non-metropolitan county in East Anglia in England. It borders Lincolnshire to the north-west, Cambridgeshire to the west and south-west, and Suffolk to the south. Its northern and eastern boundaries are the No ...
, but he was spotted and betrayed there by another slave named Will "Billy" King.
More than 70 enslaved men were arrested by law enforcement for conspiracy and insurrection.
Gabriel was returned to Richmond for questioning, but he did not submit.
The trial was heard by five justices in courts of
oyer and terminer
In English law, oyer and terminer (; a partial translation of the Anglo-French ''oyer et terminer'', which literally means "to hear and to determine") was one of the commissions by which a judge of assize sat. Apart from its Law French name, the ...
, rather than a jury. A recruit, Ben Woolfolk, testified that Gabriel intended on writing the words 'death or liberty' on a silk flag, referring to
Patrick Henry
Patrick Henry (May 29, 1736June 6, 1799) was an American attorney, planter, politician and orator known for declaring to the Second Virginia Convention (1775): " Give me liberty, or give me death!" A Founding Father, he served as the first an ...
's ''
Give me liberty, or give me death!'' speech of 1775.
One of the enslaved men reportedly said "I have nothing more to offer than what
General Washington
George Washington (February 22, 1732, 1799) was an American military officer, statesman, and Founding Fathers of the United States, Founding Father who served as the first president of the United States from 1789 to 1797. Appointed by the ...
would have had to offer, had he been taken by the British and put to trial."
Gabriel, his two brothers, and 23 other slaves were hanged.
One individual committed suicide before his arraignment. Eight enslaved men were moved or sold outside of Virginia. Thirteen were found guilty, but were pardoned by the governor. Twenty five were acquitted.
Two men received their freedom for informing their slaveholder of the plot.
Influence
The rebellion was reported in newspapers across the country. James Monroe and Thomas Jefferson were concerned about the optics of having so many people executed. Jefferson said, "the other states & the world at large will forever condemn us if we indulge in a principle of revenge." The
Federalists
The term ''federalist'' describes several political beliefs around the world. It may also refer to the concept of parties, whose members or supporters called themselves ''Federalists''.
History Europe federation
In Europe, proponents of de ...
argued that the rebellion occurred as a result of the
Democratic-Republican Party
The Democratic-Republican Party, known at the time as the Republican Party and also referred to as the Jeffersonian Republican Party among other names, was an American political party founded by Thomas Jefferson and James Madison in the early ...
's support of the French Revolution.
Fears of a slave revolt regularly swept major slaveholding communities. After the rebellion, many slaveholders greatly restricted the slaves' ability to travel after a second conspiracy was discovered in 1802 among enslaved boatmen along the
Appomattox and
Roanoke River
The Roanoke River ( ) runs long through southern Virginia and northeastern North Carolina in the United States. A major river of the southeastern United States, it drains a largely rural area of the coastal plain from the eastern edge of the App ...
s. New laws were enacted to restrict free blacks and slaves.
The Virginia Assembly in 1802 made it illegal for blacks, whether free or enslaved, to obtain and pilot or navigate a boat. Two years later, they were unable to meet in groups after their work was done or on Sundays. In 1808, state legislators banned hiring out of slaves and required freed blacks to leave the state within 12 months or face re-enslavement. The growing population of free blacks had to petition the legislature to stay in the state.
Historiography
The historian Douglas Egerton offered a new perspective on Gabriel in his book ''Gabriel's Rebellion: The Virginia Slave Conspiracies of 1800 & 1802'' (1993). He based this on extensive
primary research
Research is " creative and systematic work undertaken to increase the stock of knowledge". It involves the collection, organization and analysis of evidence to increase understanding of a topic, characterized by a particular attentiveness ...
from surviving contemporary documents.
Egerton concluded that Gabriel would have been stimulated and challenged at the foundries by interacting with co-workers of European, African and mixed descent. They hoped
Thomas Jefferson
Thomas Jefferson (April 13, 1743 – July 4, 1826) was an American statesman, diplomat, lawyer, architect, philosopher, and Founding Fathers of the United States, Founding Father who served as the third president of the United States from 18 ...
's Republicans would liberate them from domination by the wealthy Federalist merchants of the city.
The internal dynamics of Jefferson's and Monroe's party in the 1800 elections were complex. A significant part of the Republican base were major planters and colleagues of Thomas Jefferson and James Madison. Egerton believes that any sign that white radicals, and particularly Frenchmen, had supported Gabriel's plan could have cost Jefferson the presidential election of 1800. Slaveholders feared such violent excesses as those related to the
French Revolution
The French Revolution ( ) was a period of radical political and societal change in France that began with the Estates General of 1789 and ended with the formation of the French Consulate in November 1799. Many of its ideas are considere ...
after 1789 and the
rebellion of slaves in Saint-Domingue. Egerton believed that Gabriel planned to take Governor Monroe hostage to negotiate an end to slavery. Then he planned to "drink and dine with the merchants of the city".
Egerton noted that Gabriel instructed his followers not to kill white
Methodists,
Quakers
Quakers are people who belong to a historically Protestant Christian set of denominations known formally as the Religious Society of Friends. Members of these movements ("theFriends") are generally united by a belief in each human's abil ...
and
Frenchmen
The French people (french: Français) are an ethnic group and nation primarily located in Western Europe that share a common French culture, history, and language, identified with the country of France.
The French people, especially the nati ...
. During this period, Methodists and Quakers were active missionaries for
manumission
Manumission, or enfranchisement, is the act of freeing enslaved people by their enslavers. Different approaches to manumission were developed, each specific to the time and place of a particular society. Historian Verene Shepherd states that t ...
.
Legacy and honors
Gabriel's rebellion served as an important example of slaves' taking action to gain freedom.
* In 2002, the City of Richmond adopted a resolution to commemorate the 202nd anniversary "of the execution of the patriot and freedom fighter, Gabriel, whose death stands as a symbol for the determination and struggle of slaves to obtain freedom, justice and equality as promised by the fundamental principles of democratic governments of the Commonwealth of Virginia and the United States of America".
[C. Ruth Ebrahim, "Virginia State NAACP Conference requests pardon of Gabriel"](_blank)
, ''The Caroline Register'', Oct 2006, accessed 23 Jul 2008
* The Spring Park Historic Site in Henrico County commemorates Gabriel.
* In 2004, the Virginia Board of Historic Resources approved a marker at the spot where Gabriel was hanged on October 10, 1800. It is between 15th and 16th streets, on the north side of East Broad Street. The state worked with individuals from a group called the Defenders for Freedom, Justice & Equality.
* In the fall of 2006, the Virginia State Conference of the
NAACP
The National Association for the Advancement of Colored People (NAACP) is a civil rights organization in the United States, formed in 1909 as an interracial endeavor to advance justice for African Americans by a group including W. E.&nb ...
requested Gov.
Tim Kaine
Timothy Michael Kaine (; born February 26, 1958) is an American lawyer and politician serving as the junior United States senator from Virginia since 2013. A member of the Democratic Party, he served as the 38th lieutenant governor of Virgini ...
pardon Gabriel in recognition of his contributions to the civil rights struggle of African Americans and all peoples.
* On August 30, 2007, Governor Kaine informally
pardon
A pardon is a government decision to allow a person to be relieved of some or all of the legal consequences resulting from a criminal conviction. A pardon may be granted before or after conviction for the crime, depending on the laws of the ju ...
ed Gabriel and his co-conspirators. Kaine said that Gabriel's motivation had been "his devotion to the ideals of the American revolution—it was worth risking death to secure liberty". Kaine noted that "Gabriel's cause—the end of slavery and the furtherance of equality of all people—has prevailed in the light of history", and added that "it is important to acknowledge that history favorably regards Gabriel's cause while consigning legions who sought to keep him and others in chains to be forgotten".
Popular culture
*
Arna Bontemps
Arna Wendell Bontemps ( ) (October 13, 1902 – June 4, 1973) was an American poet, novelist and librarian, and a noted member of the Harlem Renaissance.
Early life
Bontemps was born in Alexandria, Louisiana, into a Louisiana Creole family. His a ...
wrote ''Black Thunder'' (1936), a historical novel based on Gabriel's Rebellion.
*Gigi Amateau wrote ''Come August, Come Freedom: The Bellows, The Gallows, and The Black General Gabriel'' (2012), an historical fiction novel based on Gabriel's Rebellion.
*In ''
Roots
A root is the part of a plant, generally underground, that anchors the plant body, and absorbs and stores water and nutrients.
Root or roots may also refer to:
Art, entertainment, and media
* ''The Root'' (magazine), an online magazine focusing ...
'',
Alex Haley
Alexander Murray Palmer Haley (August 11, 1921 – February 10, 1992) was an American writer and the author of the 1976 book '' Roots: The Saga of an American Family.'' ABC adapted the book as a television miniseries of the same name and a ...
's historical fiction, the rebellion is heard of by the book's characters.
*In ''Sally Hemings'',
Barbara Chase-Riboud
Barbara Chase-Riboud (born June 26, 1939) is an American visual artist and sculptor, bestselling novelist, and award-winning poet.
After becoming established as a sculptor and poet, Chase-Riboud gained widespread recognition as an author for he ...
's 1979 novel about
Hemings Hemings is a surname, and may refer to:
: American slavery
* Hemings family
* Elizabeth "Betty" Hemings (1735–1807), enslaved American
* Sally Hemings (1773–1835), enslaved by US president Thomas Jefferson who allegedly bore him 6 children
...
's relationship with Thomas Jefferson, Monroe writes Jefferson asking his advice on what to do about the insurrectionists still in jail after "(m)ore than thirty-five" had been executed. Hemings intercedes on their behalf, telling Jefferson, "I think there has been enough hanging", and suggests they be exiled instead. Although it is not made explicit in the novel, it is implied that Jefferson followed her suggestion and advised Monroe accordingly. At the end of the chapter, Hemings says, "I heard that the last of Gabriel's rebels had been reprieved and banished from Virginia by James Monroe. I had not pleaded in vain."
*"Gabriel, the Musical" was produced at Firehouse Theatre in Richmond Virginia September 8, 2022 through October 2, 2022. With libretto by Jerold Solomon, Foster Solomon and Ron Klipp and Music & Lyrics by Ron Klipp, the musical tells a semi-fictionalized account of thee development of Gabriel's conspiracy and its aftermath on the conspirators, the local government, and the nation. The production was funded in part by a 2020 grant from the
National Endowment for the Arts
The National Endowment for the Arts (NEA) is an independent agency of the United States federal government that offers support and funding for projects exhibiting artistic excellence. It was created in 1965 as an independent agency of the federal ...
(grant 1861109-28-20).
Songs
*
Tim Barry
Tim Barry is an American musician and the lead singer of the Richmond, Virginia-based punk rock band Avail. In addition to performing with Avail, he was the bass guitarist in the Richmond-based folk punk band (Young) Pioneers from 1994 to ...
, a singer/songwriter from Richmond, wrote and performed "Prosser's Gabriel" for the album ''28th & Stonewall''. It chronicles the events of Gabriel's life, focusing on the attempted revolution.
* Gabriel is mentioned in Public Enemy's song "Prophets of Rage".
* Gabriel is the hero of a cleverly subversive
sea shanty
A sea shanty, chantey, or chanty () is a genre of traditional Folk music, folk song that was once commonly sung as a work song to accompany rhythmical labor aboard large Merchant vessel, merchant Sailing ship, sailing vessels. The term ''shanty ...
recorded
[Frederick Marryat, ''A Diary in America'' (London, 1839)] some forty years after events in
Frederick Marryat
Captain Frederick Marryat (10 July 1792 – 9 August 1848) was a Royal Navy officer, a novelist, and an acquaintance of Charles Dickens. He is noted today as an early pioneer of nautical fiction, particularly for his semi-autobiographical novel ...
's book, ''
Poor Jack
''Poor Jack'' is a novel by the English author Frederick Marryat, published in 1840.
It tells the story of Thomas Saunders, a sailor's son and neglected street urchin struggling to survive in Greenwich, London in the early 19th century. ("Poor ...
'' (1840).
See also
*
Denmark Vesey
Denmark Vesey (also Telemaque) ( July 2, 1822) was an early 19th century free Black and community leader in Charleston, South Carolina, who was accused and convicted of planning a major slave revolt in 1822. Although the alleged plot was dis ...
*
History of slavery in Virginia
Slavery in Virginia began with the capture and enslavement of Native Americans during the early days of the English Colony of Virginia and through the late eighteenth century. They primarily worked in tobacco fields. Africans were first brough ...
*
List of enslaved people
Slavery is a social-economic system under which people are enslaved: deprived of personal freedom and forced to perform labor or services without compensation. These people are referred to as slaves, or as enslaved people.
The following is a ...
*
Nat Turner
Nat Turner's Rebellion, historically known as the Southampton Insurrection, was a rebellion of enslaved Virginians that took place in Southampton County, Virginia, in August 1831.Schwarz, Frederic D.1831 Nat Turner's Rebellion" ''American Heri ...
*
Slavery in the United States
The legal institution of human chattel slavery, comprising the enslavement primarily of Africans and African Americans, was prevalent in the United States of America from its founding in 1776 until 1865, predominantly in the South. Sl ...
Notes
References
Further reading
*
Aptheker, Herbert. ''American Negro Slave Revolts''. New York: International Publishers, 1943.
* Nicholls, Michael L. ''Whispers of Rebellion: Narrating Gabriel's Conspiracy''. Charlottesville, VA: University of Virginia Press, 2012.
* Schwarz, Philip J.
Gabriel's Challenge: Slaves and Crime in Late Eighteenth-Century Virginia, ''Virginia Magazine of History and Biography'' Volume 90, Issue 3, pp. 283–309, 1982.
* Schwarz, Philip J. ''Gabriel's Conspiracy: A Documentary History.'' Charlottesville: University of Virginia Press, 2012.
* Rodriguez, Junius P., ed. ''Encyclopedia of Slave Resistance and Rebellion''. Westport, CT: Greenwood, 2006.
External links
* The Collegian, [https://www.thecollegianur.com/article/2022/10/community-gathers-for-20th-annual-gabriel-gathering-at-shockoe-bottom-african-burial-ground Community gathers for 20th Annual Gabriel Gathering at Shockoe Bottom African Burial Ground]
* Richmond Magazine
Nice Shot: Illumination and ReclamationThe 20th annual Gabriel Gathering at the African Burial Ground in Shockoe Bottom Nov 8, 2022
* Black Agenda Report
Commemorating Gabriel's Rebellion at the African Burial Ground in Richmond, Virginia Sept 30, 2022
{{DEFAULTSORT:Prosser, Gabriel
1776 births
1800 deaths
18th-century executions of American people
American rebel slaves
18th-century American slaves
Conflicts in 1800
Executed African-American people
Executed revolutionaries
History of Richmond, Virginia
History of slavery in Virginia
People executed by Virginia by hanging
People from Henrico County, Virginia
Executed people from Virginia
Recipients of American gubernatorial pardons
Slave rebellions in the United States