Her mother was Judith Lewyn Isham (d. 1625), daughter of William Lewin, who was an educated Anglican judge of the Prerogative Court of Canterbury and a master in chancery.
Her royalist brother Justinian (1610-1675), the second baronet of Lamport, left for Oxford during the English Civil War, leaving Elizabeth to care for her father and four nieces, and to manage the estate.
[3]: 11 As a young woman, Isham had to decide whether to obey her father's wishes to marry and raise a family, or to remain single in order to devote her life to God.
Isham spent most of her life at her family estate of Lamport Hall in Northamptonshire, but she did on occasion visit relatives in London.
[3]: 13 The capital city provided greater opportunities for a young woman to find a suitable marriage partner, so when aged eighteen Isham was sent by her father to stay there with her uncle, James Pagitt.
[4]: 109 Isham's choice to reject marriage resulted from both the hardships faced from her failed relationships and difficult decisions made of her devotion to God.
[3]: 24 This freedom during the 17th century for women was rare and eventually opened doors to a whole new light that being single was not strict grounds for rejection in society.
[3]: 25 Another reason for staying single may have been that Isham enjoyed solitude and privacy to pray and to spiritually connect with God, given that "she often preferred to be alone, busying herself with work".
[1]: 241 Although she never had children, Isham helped her brother to raise his four young daughters after his wife, Jane, died soon after giving birth to a son.
[5]: 123 Isham's great-grandmother was a skilled surgeon, and her aunt was a strong motivator to drive her to pursue herbal knowledge through borrowed books.
[5]: 123 Isham's familial inheritance of females who already had medical knowledge, gave her the "authoritative background" necessary to pursue her interest in herbalism.
[1]: 234 Cotterill mentions that from an early age, Isham "constantly read, copied down, studied, memorized, and repeated prayers, psalms, chapters of the Bible, excerpts from collections of biblical 'places,' literary texts, and sermons".
[1]: 230 Around 1638–1639 when Isham was 30, she composed her first extensive work called My Booke of Rememberance, where she recorded her thoughts, beliefs, explanations for her decisions, her struggles, and the freedom of her single life.
[4]: 97 She specifically talked about her struggles in dealing with the loss of her mother and sister who were close to her, the unsuccessful relationship between her and her father's recommended suitor, and her quest for a single life.
Julie Eckerle mentions that Isham was strikingly independent in all matters, from poetry, ballads, and herbals to playing cards and reading romances.
This second diary has come to public attention recently and is housed at Princeton University Library, Robert H. Taylor Collection (RTC 01 no.62).