Rufus King (1755-1827) spent parts of all three of his terms in the Continental Congress (1785-1787) trying to untangle the conflicting claims to 13 million acres of land in central and western New York. In 1783, Massachusetts reasserted its claim to land east of the western border of New York based on the 1644 colonial charter granted by King Charles I, which gave Massachusetts a strip of territory to the Pacific Ocean. New York disagreed and as mandated by the Articles of Confederation, both sides agreed to set up a federal court to settle the issue. That proved harder than expected, and both sides agreed to meet in direct negotiations at Hartford, Connecticut on November 30, 1786. Ten agents, four from Massachusetts and six from New York, worked until December 16 and came up with a compromise that gave sovereignty of the land to New York, but gave title to a little more than six million acres to Massachusetts. The historian Wendell Tripp referred to this acquisition of Massachusetts as “a pocket-size empire in a state of virginity.” The legislatures of both sides ratified the agreement in 1787 and Massachusetts was able to raise funds from the tract by selling the title to a land syndicate for roughly three cents an acre in April 1788.
By any measure, it was a success for King and the other Massachusetts agents. It also marked the first time King was involved in negotiations over boundaries. He would be involved with many other political and diplomatic battles over borderlines in the future, especially when he was the American minister to Great Britain from 1796-1803. This work required King to have access to massive amounts of often-obscure historical and legal information to formulate strong arguments. It was part of the reason why his Americana collection was so strong and why he purchased so many maps while in London. His initial work in 1785-1786 offers a glimpse of his research process that would be refined over time.
The Massachusetts-New York land dispute involved the detailed study of sixteenth and seventeenth and century exploration and colonization. One gets the sense of the vast corpus of material that had to be mined in order to fully synthesize the problems by looking at the records left behind by Alexander Hamilton, who was hired as one of the counselors for the New York agents. Hamilton used eight important colonial history books and one pamphlet to put together a timeline of explorations and land claims in North and South America generally and Canada, New England, Virginia, and New York specifically. In all, the notes take up eleven printed pages in the Papers of Alexander Hamilton.
Massachusetts did not hire any legal help, but King undertook a similar research project, seeking out information on the boundaries specified in the several colonial charters from Massachusetts to Georgia and recording it in a notebook preserved at the New-York Historical Society. King went to the second volume of the Parliamentary Register from 1774 to excerpt material from the charters and used George Chalmer’s Political Annals of the Present United Colonies, from the Settlement to the Peace of 1763 to find several small details on the charters. He also used William Smith’s The History of the Province of New-York to locate material from the New York and New Jersey charters. Throughout the notebook, King underlined sections dealing with boundaries extending from the Atlantic to the Pacific, the basis of the Massachusetts argument for the land.
As a well-connected Congressman, King knew the New York agents, who shared reports and maps with him before the negotiations. King knew the likely strategy of his adversaries: “[New York] will prove a possession prior to the first massachusetts charter; and produce ancient maps to shew that the whole country west of the Hudson was laid down at the as nova Belgia; then arguing from the municipal principle, that a possession of a part, ensures to all the beneficial purposes of a possession of the whole Territory claimed attempt the establishment of their title by possession.” To counter this, King suggested looking at the Dutch records in New York and examining records in London. John Adams, the American minister in London at the time, followed up on King’s request and had the pertinent documents copied at the high cost of fifteen guineas. Also, King looked to William Smith’s The History of the Province of New-York, “which cites an old author, whose name I don’t remember, who considers the territory west and north west of Albany as Terra incognita.”
King also knew the New Yorkers were examining colonial Massachusetts law and he recommended it, “would be well to examine every act of Massachusetts on this subject that may be obtainable; and perhaps the Laws fixing the county lines may by incautious expressions express some precise Limit to our western Line.” King also wanted to know what the reports of governors from Massachusetts and New York back to England said about the dispositions of each colony and a search of the records for Indian applications for protection, “any thing of that kind, from the western indians, to Massachusetts in early times, would weight well against the claim of the dutch defendants and therefore should be looked after.”
In addition, King worried about New York’s strongest argument, the quo warranto proceedings of 1684 that revoked Massachusetts’ original charter, and led to a new charter in 1691. King challenged this argument in a legal manner, doubting “if any jugement [sic] was entered in form, which Hutchinson doubts in his history.” Thomas Hutchinson’s The History of the Colony of Massachusetts-Bay provided a summary of the events of that led up to the new charter, “but nothing particular can be concluded from his history; if an authentic report of that case can be obtained, it might be very serviceable.” King also remembered a declaration made by the governor of Massachusetts in 1676, suggesting that the colony extended to the Pacific, and “this paper is in Belknap’s History of New Hampshire, appendix paper 14. – the paper No. 15 in the same appendix, containing a report of the board of trade, throws light up on the same subject.”
It is clear that part of the success of the Massachusetts’ agents involved the research preparation of King. His personal connections no doubt made the negotiations easier, but the arguments of King and his colleagues gave traction to a weak argument and led to a compromise that benefited their state. Books and documents proved the longevity of the Massachusetts claim and those arguments made the New Yorkers accommodate their adversaries. In part, it was the use of books and documents that led to a political victory that brought hundreds of thousands of dollars into the state coffers at a time when it was sorely needed.
 Massachusetts ceded all their western lands between the Mississippi River and the western border of New York in April 1785. King and his fellow Massachusetts delegate Samuel Holten formerly performed this duty in Congress.
 Wendell Edward Tripp, Jr., Robert Troup: A Quest for Security in a Turbuent New Nation, 1775-1832 (New York: Arno Press, 1982), 156.
 This syndicate, run by Oliver Phelps and Nathaniel Gorham, also had to buy the land rights from the Indians already living there. They purchased the title of 2.5 million acres of land from the Indians, but were unable to keep up with payments on the land and sold 1 million acres of the eastern part of the tract to Robert Morris and had to return the western 2/3rds to Massachusetts. See Tripp, Robert Troup, 154-155.
 Harold C. Syrett, ed., The Papers of Alexander Hamilton, Volume 3 (New York: Columbia University Press, 1962), 704-711.
 RK Papers, N-YHS, Vol. 105.
 James Duane to RK, January 1787, Houghton Library, “a duplicate of Mr De Witt’s map of the disputed territory, used in the late interesting negociation [sic].”; RK to John Lowell, 25 April 1785, Houghton Library, Harvard University (bMS AM 1582, 308-317) which notes sending a report written by John Jay “relative to our eastern boundary – I do not like it – pray shew [sic] it to those whom it may concern under the injunction of secrecy.”
 RK to John Lowell and James Sullivan, 23 April 1785, Houghton Library, Harvard University (bMS Am 1582, 308-317).
 These records were sent by John Adams in London: RK to Lowell, Sullivan, and Parsons, 12 April 1786, Houghton Library, “By the last Packet I received from Mr. Adams an attested copy of the Letters patent of King James the 1st. to the council of Plymouth, together with the papers, copies whereof are inclosed – The copy of the letters patent is voluminous; and I have supposed it as well to keep in my possession as to transmit it by Post.”
 RK to Lowell and Sullivan, 23 April 1785