Of all the claims made in Flagellum, none is more unexpected than that William Welbore was ‘a Kinsman of Cromwells’. If true, this would be a surprising addition to our knowledge of Oliver Cromwell's family connections. Cromwell's genealogy has been more intensively studied than that of any other English commoner of the seventeenth century, with the possible exceptions of William Shakespeare and Samuel Pepys. Whole books have been written on the subject. None of those historians and genealogists who have explored the remoter byways of the Cromwell family tree have found the slightest trace of any link between Cromwell and Welbore. A search through the extensive literature on the Cromwell family would therefore lead one to conclude that this particular statement in Flagellum was almost certainly incorrect. And yet the statement is true.

The Welbores of Foxton were one of the more minor gentry families of Cambridgeshire. William's father, Philip Welbore, who was originally from Clavering in Essex, had settled at Foxton, a village seven miles to the south of Cambridge, by the 1570s. The land within the Foxton parish boundaries was fragmented between a number of different landowners, not all of whom lived there, so Philip's purchase of ninety-six acres in 1591 had been enough to ensure that the Welbores became the parish's leading residents.