George Mason IV, our university namesake, learned important lessons about plantation management from his childhood mentor and uncle John Mercer, an immigrant from Dublin, Ireland, who loved collecting books. Mercer (1704-1768) compiled one of the largest libraries in 18th-century Virginia; his shelves contained medical manuals, science journals, and law treatises from local jurisdictions and neighboring Maryland. Having developed expertise in torts, Mercer became a hard-charging lawyer who represented gentry before the colonial bench, including in courts of Fairfax County. His most prominent client was George Washington. Mercer’s harsh treatment of legal opponents earned him enemies, among them Robert “King” Carter, a rival of the Mason family. Carter received his royal designation because he was the “Chesapeake monarch” of slaveowners, holding more than one thousand people of African descent in rightless subjugation. 
Mercer came to the attention of George Mason II who married his daughter Catherine Mason to this ambitious Irish litigator. By the late 1720s, Mercer was a powerful son-in-law with access to his wife's family capital. At the time, he began to purchase lots in Marlborough, a failing town in present-day Prince William County. There, Mercer established plantations covering sixty thousand acres. By 1753, Mercer had imported 100-plus enslaved individuals, many of them from the Bight of Biafra in West Africa (contemporary Nigeria). Having survived the Middle Passage, captives of slave ships in northern Virginia were taken to makeshift harbors along the Potomac River. One of these disembarkation points was the Colchester ferry site, an entrepot that George Mason IV would operate for decades. Located in a narrow inlet, Colchester is a two-hour walk from his Gunston Hall Plantation. Fully half of the African people Mercer acquired as chattel and dehumanized on his farms between 1731 and 1750 escaped or died; documented causes of death note suicide. Mercer’s overseers were known for their cruelty.
Researchers in the Center for Mason Legacies (CML) have just gained access to the original pages of John Mercer’s handwritten account book housed in the Pennsylvania Bucks County Historical Society. Revealing evidence of his investment in human trafficking, this ledger also identifies the slaveholders with whom Mercer transacted deals. For example, a June 1738 entry inventories a shipment of enslaved West Africans landed in the Chesapeake region. An accompanying folio, titled “Negroes,” lists four of the stolen people (Ajax, Oroonoko, Dido, and Beauty). Mercer acquired them for 91 pounds sterling. Additional jottings report how he disaggregated the purchase sum, “with 70 pounds” going to the vendor and the remaining amount presented as “the duty.” Mercer sold captives to various buyers, among them Col. George Mason III, his brother-in-law, and Sir William Gooch, the colonial governor.  (See image for details of these transactions). Col. Mason soon went from paying money to Mercer to making money with Mercer. They hired Virginia-based sailing captains with links to Liverpool financiers of the trans-Atlantic slave trade and outfitted a sloop with “Anchors & Cables” to convey “cargo” on the Potomac. The transport trade brought Mercer and Mason closer together. The former was entrusted by his business partner to be the co-executor of the Mason estate, which George Mason IV received after his father’s death.
The legacies of people selected to represent our university in the built environment need to be examined more thoroughly. With funds for expansive fieldwork and paid student researchers, CML stands ready to explore the history of John Mercer and others named on our campus buildings.
 Title excerpted from John Mercer Ledger, 1734 August- 1750 April, N.P., Bucks County Historical Society, Doylestown, Pennsylvania.
 George Mason IV obtained his legal expertise and vast library from John Mercer: Kate Mason Rowland, The Life of George Mason, 1725-1792: Including His Speeches, Public Papers, and Correspondence, vol. 1 (New York: G.P. Putnam’s Sons, 1892). 52; Jeff Broadwater, George Mason, Forgotten Founder (Chapel Hill: University of North Carolina Press, 2006). 3.
 A Compleat Collection of the Laws of Maryland (1727); An Exact Abridgement of the Laws of Virginia (1737); Broadwater, George Mason, Forgotten Founder, 3. J.A. Leo Lemay, “Mercer, John (1705-1768), lawyer and writer,” American National Biography; accessed 31 August 2019. https://www-anb-org.mutex.gmu.edu/view/10.1093/anb/9780198606697.001.0001/anb-9780198606697-e-0101169; Lorena Seebach Walsh, Motives of Honor, Pleasure, and Profit: Plantation Management in the Colonial Chesapeake, 1607-1763 (Chapel Hill, North Carolina: Published for the Omohundro Institute of Early American History and Culture, Williamsburg, Virginia, by the University of North Carolina Press, 2010). 517.
 A. G. Roeber, Faithful Magistrates and Republican Lawyers: Creators of Virginia Legal Culture, 1680-1810 (Chapel Hill: University of North Carolina Press, 1981). 77; Alan McKinley Smith, “Virginia Lawyers, 1680-1776: The Birth of an American Profession” (Ph.D. Thesis, The Johns Hopkins University, 1967); Landon Carter, The Diary of Colonel Landon Carter of Sabine Hall, 1752-1778. (Charlottesville: University Press of Virginia, 1965), 93.
 Mercer built a long brick home at the cost of six hundred pounds sterling, a massive sum in the early 18th century. This property was augmented by several outbuildings, a warehouse, riverside wharf, and windmill.
 John Mercer Ledger, N.P. Bucks County Historical Society, Doylestown, Pennsylvania; Lorena Seebach Walsh, Motives of Honor, Pleasure, and Profit: Plantation Management in the Colonial Chesapeake, 1607-1763 (Chapel Hill: Published for the Omohundro Institute of Early American History and Culture, Williamsburg, Virginia, by the University of North Carolina Press, 2010). 514-18.
 John Mercer Ledger, N.P., Bucks County Historical Society, Doylestown, Pennsylvania.
 John Mercer Ledger, N.P., Bucks County Historical Society, Doylestown, Pennsylvania. Members of small seafaring fraternity, the sailing captains likely worked for the Gildart family and its Liverpool creditors, who financed slaving voyages between Africa, James River settlements, and England. George Mason IV’s younger brother, Thompson Mason, a Colchester ferry stakeholder, sold enslaved people for the Gildarts. See data on the Upton, the Gildart- and (Abraham) Barnes-owned slave ship: “Voyage of ‘Upton,’” Trans-Atlantic Slave Trade Database, 1761; accessed 27 February 2021. https://www.slavevoyages.org/voyage/database. Abraham Barnes was Thompson Mason’s father-in-law.
March 02, 2021