William Peters (1702- September 8, 1789) was an English lawyer and amateur architect from Liverpool who lived in Philadelphia for nearly three decades before returning to England. He built Belmont Mansion, one of the earliest villa-retreats on the banks of the Schuylkill River, and laid out formal gardens there.
Peters arrived in Pennsylvania in 1739 and embarked on a lucrative private law practice. Guided by his taste for luxury and his pretensions to high social status, he purchased, in July 1742, a 220-acre parcel of land on a commanding position on the west side of the Schuylkill, which he named Belmont.  He immediately began to develop the property in a remarkably ambitious and sophisticated manner. Conceiving of Belmont as an Epicurean retreat, he designed a Palladian-style villa (one of the earliest in America) and extensive pleasure gardens. Belmont evidently established Peters’s reputation as an amateur gentleman-architect and he was often called upon to provide his Philadelphia neighbors with expertise in architectural matters. In 1743, while mulling plans for a new residence at his country estate Springettsbury, directly opposite the river from Belmont, the Proprietor of Pennsylvania, Thomas Penn, informed Peters, “I hope to have the pleasure ere long of visiting your Country Retirement and gaining something by your experience.”  Writing to Penn a few years later, the Philadelphia merchant Richard Hockley praised the plan Peters had drawn up for a townhouse as “a very compleat one, of the dimensions, and the best I think by far in this place and most convenient and commodious.”  Peters went on to supervise the construction of a ferry house on the Delaware River for Penn, and to advise Benjamin Chew on plans for a country house he intended to build in the Germantown neighborhood near Philadelphia. 
Peters’s introduction to the Penn family came through his younger brother, the Anglican Rev. Richard Peters (1704 – 1776), who had immigrated to Philadelphia in 1735 and secured Thomas Penn’s patronage soon after. William Peters provided legal services to the Penns and through their agency gained appointments to a number of profitable public offices, including Notary Public for Pennsylvania (1744), Register of the Admiralty Court of Pennsylvania (1744), and Justice of the Peace and of the Courts of Common Pleas, Quarter Sessions, and Orphans. (1757)  Over the years, Thomas Penn became concerned by the degree to which building and landscape work at Belmont were distracting Peters from his official duties. In 1752 the Rev. Richard Peters felt obliged to apologize for his brother’s extravagant expenditure of capital and attention at Belmont, acknowledging in a letter to Penn that William’s “country schemes had well night ruined him, & [the] hurt done to his circumstances by their expense was not half so great as that done by a dissipation of mind.” He nevertheless assured Penn that “now he is come to town & in full business I am in hopes he will do much good.”  Despite this reassurance, William Peters apparently continued to devote himself to rural retirement at Belmont while neglecting his business in town, prompting Penn, in a letter of 1760, to make the pointed observation, “He may, I think fix some office hours, so as to have time for his Air, Exercise and Retirement.”  Penn allowed William Peters to succeed his brother Richard as secretary of the Pennsylvania Land Office in 1760. Peters served in that office for five years, seeking to use his position to supplement his income and expand his property holdings by raising warrant and patent fees and purchasing land under false names.  This self-dealing led to a final rift with Penn, who dismissed Peters from office in 1765. Peters returned to England in 1768, settling in Knutsford, Cheshire.  He created a deed of trust leaving Belmontin the care of his eldest son, Richard Peters, to whom he legally transferred the estate and all his other Pennsylvania properties in 1786.  Peters continued to pursue his interest in horticulture after returning to England. In his 84th year, he sent parcels of flower seeds to his son and daughter in Philadelphia, informing them in a letter of January 8, 1787: “The seeds consist of an amazing variety of sorts, and if you are as fond of flowers as I am, they will afford you a great deal of pleasure and I shall be glad to hear from you how they succeed.” 
- The Rev. Richard Peters to Thomas Penn, June 20, 1752 (quoted in Reinberger, 1998: 36)
- “His [William Peters’s] country schemes had well nigh ruined him; & hurt done to his circumstances by their expense was not half so great as that done by a dissipation of his mind. He is a very honest & capable man & now he is come to town & in full business I am in hopes he will do much good. I am persuaded when you come to see what assiduity & care he can take & what understanding he shows in the draughts of his papers you will be able to make him of great use to you in your own affairs.”
J. Smith Futhey and Gilbert Cope, History of Chester County, Pennsylvania, with Genealogical and Biographical Sketches (Philadelphia: Louis H. Everts, 1881): https://archive.org/details/cu31924005813518 Evidence for Benj. Franklin episode: http://founders.archives.gov/?q=%22william%20peters%22&s=1111311111&sa=&r=9&sr=; http://founders.archives.gov/documents/Franklin/01-30-02-0165; etc.
- Richard Peters, Jr., “Belmont Mansion,” Proceedings of the Numismatic and Antiquarian Society of Philadelphia, 30 (1925): 78-79, view on Zotero.
- Thomas Penn to William Peters, August 22, 1743, quoted in Mark Reinberger, “Belmont: The Bourgeois Villa in Eighteenth-Century Philadelphia,” Arris: Journal of the Southeast Chapter of the Society of Architectural Historians, 9 (1998): 17. view on Zotero. For the involvement of “Mr. Peters” in Penn’s plans for a projected residence at Springettsbury, see Richard Hockley to Thomas Penn, June 27, 174 in Richard Hockley, "Selected Letters from the Letter-Book of Richard Hockley, of Philadelphia, 1739-1742 (Continued)," The Pennsylvania Magazine of History and Biography, 27 (1903): 435, view on Zotero.
- Richard Hockley to Thomas Penn, April 18, 1749, quoted in Reinberger, 1998, 18, view on Zotero.
- Reinberger, 1998: 18.
- John Hill Martin, Martin’s Bench and Bar of Philadelphia: Together with Other Lists of Persons Appointed to Administer the Laws in the City and County of Philadelphia, and the Province and Commonwealth of Pennsylvania (Philadelphia: Res Welsh & Co., Publishers, 1883), 9, 33-34, 45, view on Zotero.
- The Rev. Richard Peters to Thomas Penn, June 20, 1752, quoted in Reinberger, 36, n.17, view on Zotero.
- Thomas Penn to the Rev. Richard Peters, November 15, 1760, quoted in Reinberger, 1998: 27, view on Zotero.
- Munger, 1991, 96, view on Zotero.
- John W. Jordan, ed., Colonial Families of Philadelphia, 2 vols. (New York and Chicago: The Lewis Publishing Company, 1911), 2: 1107, view on Zotero.
- Black, 1904, 61, 91, view on Zotero.
- Nellie Peters Black, Richard Peters, His Ancestors and Descendents: 1810-1889 (Atlanta: Foote & Davies, 1904), 36, view on Zotero.