John Knapp, father of the Puritan gateway Judith Knapp, had a 1st cousin, Mirabel Poley, who was descended from Edward III on her mother's side.
She married a William Brewster, previously married to Anne Clopton. He was bailiff, constable and gamekeeper at Castle Hedingham in Essex for the Earl of Oxford.
According to Burke, William had 2 sons called William, one by each wife.
https://archive.org/details/b24877876_0002/page/338
According to a later pedigree by Crisp, which I haven't seen, one of those sons, born 1562, became a keeper of prisoners (mostly Jesuits). The ref given is Visn. of England and Wales, Notes, Vol X, p.160.
According to John G Hunt, who compared the handwriting, the jailer was the same William Brewster who sailed with Capt John Smith in 1607 and was killed by Indians later the same year.
https://www.jstor.org/stable/4247341?read-now=1&seq=1#page_scan_tab_contents
Mirabel Poley and her husband had a daughter Anne Brewster, who had 3 husbands, the middle one being Sir Thomas Seckford or Sackford.
And according to Douglas Richardson, Mirabel Poley was the ancestor of a Thomas alias Sackford Brewster, of Surry County VA.
https://books.google.co.uk/books?id=8JcbV309c5UC&pg=RA1-PA507
But no source cited. Same note in RA Vol. 3 p. 351.
This Thomas/Sackford Brewster doesn't seem to have a profile, which probably means he doesn't have any descendants.
All I can find is that he went with Edward Bland on the expedition that opened up North Carolina.
https://archive.org/details/discoveryofnewbr00blan/page/n7
Anybody know any more? Especially, how this Sackford Brewster connects? Seems like he must have been a great-nephew of William who died in 1607. And which wife was that William's mother?
Incidentally, John G Hunt lived in Virginia. It seems to have been the Virginia Brewsters who led to his interest in Brewster matters generally. In fact the Brewster of Jamestown 1607 had previously been placed as a son of Mayflower Brewster and his wife, whoever she was, though it turns out the two pioneering namesakes were about the same age.