During the court cases, the prosecution kept changing the grounds of accusation, ending with linking the insurrection to a "Popish" plot by Spaniards and other Catholics.

Rumors of a conspiracy arose against a background of economic competition between poor whites and slaves; a severe winter; war between Britain and Spain, with heightened anti-Catholic and anti-Spanish feelings; and recent slave revolts in South Carolina and Saint John in the Caribbean.

In March and April 1741, a series of 13 fires erupted in Lower Manhattan, the most significant one within the walls of Fort George, then the home of the governor.

The bodies of two supposed ringleaders, Caesar, a slave, and John Hughson, a white cobbler and tavern keeper, were gibbeted.

The governor of New York in 1737 told the legislature, "the artificers complain and with too much reason of the pernicious custom of breeding slaves to trades whereby the honest industrious tradesmen are reduced to poverty for want of employ, and many of them forced to leave us to seek their living in other countries.

An economic depression contributed to declining food and fuel supply, aggravated by record low temperatures and snowfall.

[7] In addition, Britain experienced increased hostilities with Spain, which added to the anti-Catholic and anti-Spanish feelings by the authorities.

By 1700 the New York anti-priest law utterly outlawed the presence of Catholic priests under penalty of life imprisonment.

This incidence was particularly notable because the 1713 Treaty of Utrecht gave the British a thirty-year right to supply an unlimited number of slaves to Spanish colonies with an additional 500 tons of goods each year.

[citation needed] Initially tackling the problem of stolen goods and Hughson's tavern, the city council decided to launch an investigation.

Horsmanden set up a grand jury that he "directed to investigate whites who sold liquor to blacks – men like John Hughson."

Given legal practice then and his own inclinations, he exercised great influence in interrogations and directing the grand jury's investigations.

[citation needed] John Hughson was a poor, illiterate cobbler who came to New York from Yonkers in the mid-1730s with his wife, daughter, and mother-in-law.

In February, two weeks before the first fire, Hughson was arrested for receiving stolen goods from slaves Caesar and Prince, who were also jailed.

)[citation needed] Horsmanden, one of three justices on the court and leader of an investigation, pressured 16-year-old indentured servant, Mary Burton, to testify against her master Hughson on theft charges.

[citation needed] Although Burton's testimony did not prove that any crime had been committed, the grand jury was so afraid that more fires would occur that they decided to believe her.

The board of inquiry requested the lieutenant-governor to issue a proclamation offering a reward to anyone providing information leading to the conviction of anyone setting fire to any dwelling or storehouse in the city: £100 to a white person, £45 to a free black or Indian, and £20 and freedom to a slave.

Respectable white men whose testimony normally would have been given considerable weight, they stated that each of the slaves had been at home the evening in question.

"[16] An anonymous letter was sent to the city of New York, cautioning them against the epidemic of suspicion and executions, as the writer claimed to have seen in the Salem witch trials.

But at the time of the trial, Horsmanden had received a warning from the governor of Georgia that Spanish agents were coming to burn all the considerable towns in New England.

James Ogelthorpe, founder and governor of Georgia, sent word to Prosecutor Joseph Murray that the Spanish were planning a secret invasion of the British colonies: A party of our Indians returned the eighth instant from war against the Spaniards.

They had an engagement with a party of Spanish horse, just by [St.] Augustine…And they brought one Spainiard prisoner to me… Some intelligence I had of a villainous design of a very extraordinary nature and, if true, very important, viz.

that the Spaniards had employed emissaries to burn all the magazines and considerable towns in the English North America, thereby to prevent the subsisting of the great expedition and fleet in the West Indies.

And for this purpose many priests were employed who pretended to be physicians, dancing masters, and other kinds of occupations, and under that pretence to get admittance and confidence in families.

[20] Oglethorpe's letter left little doubt that the colony was part of an international conspiracy, one which not only planned to infiltrate and destroy the city of New York, but also to engage its Protestant citizens in religious warfare.

[22] The following year, Mary Burton finally received her reward of £100 from the city, which she used to buy her freedom from indenture, and had money left over.

North of there was the African Burial Ground, which was rediscovered in 1991 during survey work for construction at 26 Federal Plaza in lower Manhattan.

[citation needed] Mary Burton, Sarah Hughson, and Peggy Kerry were three women whose testimony was instrumental in the outcomes of the trials during the slave revolt.

[25] There is some suggestion that the 1741 New York panic may have also led to burning at the stake of individuals from New Jersey's enslaved population, as then-Essex County records suggest (according to accounts written in the 19th and early 20th centuries) that locals were openly reimbursed for the costs of irons and wood for pyres.

Under a New Jersey law passed in 1713 that authorized slave punishment by burning at the stake, it is reported, numerous individuals were so executed prior to the Revolution.