Research Notes:
John Fitz-Herbert, Lord of Norbury, reportedly married Agnes, daughter and heiress of Osbert de Stretton, of Etwall, Derbyshire, and had son John. [1]
John Fitz-Herbert, Lord of Norbury, reportedly had son, another John Fitz-Herbert, of Norbury. [2] [3]
[1] Charles Mosley, ed., Burke's Peerage, Baronetage, & Knightage, 107th edition, Vol. 3 (Willington, Delaware: Burke's Peerage & Gentry, LLC, 2003), 3710.
[2] Sir William Dugdale, Derbyshire visitation pedigrees, 1569 and 1611 (London: 1895), 35, [HathiTrust], [GoogleBooks].
[3] John Burke, A Genealogical and Heraldic History of the Commoners of Great Britain and Ireland, Vol. 1 (London: Henry Colburn, 1834), 78, in "Fitz-Herbert of Norbury and Swinnerton," pp 78-82, [GoogleBooks].