Returning to Lamport, Sir Thomas contracted to marry Mary van de Bempde, the daughter of a Dutch merchant, but he died of smallpox in London on 26 July 1681 before his marriage could take place.Burdon (1960), p. 1–25.Isham (1969). He was buried several days later on 9 August in Lamport, and succeeded in the baronetcy by his younger brother Sir Justinian Isham, who became the 4th baronet.
