European contact occurred in the first half of the 1600s. A map in the possession of Reverend Henry Whitfield from a 1639 deed shows the island and the Quinnipiac name of "Massancummock". In 1641, Whitfield and the founders of Guilford purchased the island from the Mohegan tribe's sachem, Uncas, as part of a transaction for the land east of East River. Uncas acquired the land when he married the daughter of the Hammonassett sachem, Sebequanash. At some point in the 1600s, Andrew Leete was an owner of the island. In 1715, Caleb and Ebenezer Stone purchased the island and it remained in the Stone family until 1801. In 1800, Noah Stone sold it to a distant relative named Medad Stone for $158.34 (). On May 12, 1801, Medad Stone sold the island to the government for $325 (). Joel Helander, a historian, notes that Medad Stone and the government were likely openly communicating about the island. The United States Congress appropriated $6000 in March 1801 for the lighthouse, prior to the government's acquisition of the property.