Thomas Cooper married "By about 1642, Sarah Slye, baptized Lapworth, Warwickshire, 29 October 1615, daughter of George Slye [TAG 57:93] … She married (2) Springfield 15 November 1676 'Lieut. William Clarke, of Northampton' [Pynchon VR 59]." Eldest daughter, Sarah, was "15 or 16 years" in December 1657 and 18 in May 180, according to John Winthrop, Jr.'s medical journal.