Edmund was the child of Sir John Brokesbourne’s old age. Sir John had produced four sons by his first wife Elizabeth (d.1326) and had sat in Parliament for Essex three times (in 1316, 1327 and 1328) before his marriage to Edmund’s mother, Margery Whelnetham. He had procured from Edward II charters of free warren in his lands at Bradfield, Mistley, Wrabness, Ramsey, Dovercourt, Wix and Tendring and for a market and fair at Bradfield, and when he died (in 1342) the heir to these properties was his son Robert, aged over 30. However, in the following year Robert relinquished Bradfield to his stepmother and her son and they later acquired the other estates, too. Margery then married
Sir John Sutton
† (d.1369) of Wivenhoe, head of one of the most influential families in Essex, and as a consequence Edmund was to be always closely connected with Sutton’s sons,
Sir John
† (d.1393) and Sir Richard (d.1396). It was not until 1385, when Margery died, that Brokesbourne, then aged over 45, obtained full possession of his inheritance, which included his mother’s manors of Great Whelnetham and Alpheton in Suffolk.
According to the testimony Brokesbourne gave in the court of chivalry in 1386 (in the dispute over certain heraldic arms brought by John, Lord Lovell, against Thomas, Lord Morley), as a young man he had served at sea under the command of Morley’s grandfather, Lord Robert, when he was admiral; he had then taken part in Edward III’s campaigns in France in 1359-60; and had subsequently followed Thomas de Vere, earl of Oxford, in the duke of Lancaster’s army which attempted to seize Harfleur in 1369. He recalled seeing the contested coat of arms borne by the Morleys on each of these expeditions, and further recounted what his late stepfather Sutton had told him about the banners displayed by Lord Robert at the siege of Calais. At a comparatively recent, although unspecified date, he himself had married a daughter of that lord, but nevertheless now made formal affirmation that he was in no way biased in the defendant’s favour. From the beginning of Richard II’s reign Brokesbourne had figured on royal commissions, notably for the defence of Harwich in case of attack by the French. He was much involved in the Suttons’ affairs, often witnessing their deeds and joining them in transactions with John, 2nd Lord Bourgchier, whose son Bartholomew married Margaret Sutton (possibly his own half-sister). Brokesbourne’s mother and stepfather had both been named as executors of the will of Maud de Vere, countess of Oxford (d.1366), and the younger Sir John Sutton was also connected with the comital family.
Brokesbourne continued to act as a trustee of the Sutton estates and as a witness to local conveyances until his death, which occurred at an unknown date between July 1396 and May 1397.
