After the adoption of the United States Constitution in 1787, the federal government ratified the states' compact. In April 1788, Phelps and Gorham bought the preemptive rights from Massachusetts, but this did not get them the right to develop or re-sell the land. They only obtained exclusive right to negotiate with the Iroquois and obtain clear title to the land. For this preemptive right, they paid Massachusetts $1,000,000 (£300,000) (equivalent to about $ million today) or 16 and 2/3 cents an acre ($41.18/km2). This was to be paid in three annual installments.