[4] Lilly's autobiography, published towards the end of his life in 1681, at the request of his patron Elias Ashmole, gives candid accounts of the political events of his era, and biographical details of contemporaries that are unavailable elsewhere.

[7] In it, Lilly describes the friendly support of Oliver Cromwell during a period in which he faced prosecution for issuing political astrological predictions.

[5] His biography records his disappointment at being denied the opportunity that all of his fellow students enjoyed, even though he describes the knowledge of most of them as "defective": [A]ll and every of those scholars who were of my form and standing went to Cambridge ... only poor I, William Lilly, was not so happy; fortune then frowning upon father's present condition, he not in any capacity to maintain me at the university.

[16]A lesser opportunity came through his father's attorney, who recognised Lilly's level of education and recommended him to Gilbert Wright, Master of the Salters' Company and resident of the Strand in London (but formerly of Market Bosworth, Leicestershire).

[17] With his letter of recommendation and just a few shillings, eighteen-year-old Lilly walked to London alongside a carrier's cart, later recounting "it was a very stormy week, cold and uncomfortable: I footed it all along".

[21] The comfortable lifestyle and fortune that Lilly inherited from Ellen, gave him leisure time to frequent sermons and lectures in London society.

[2] In 1632, shortly before Ellen's death, he began to study astrology, reading all the books on the subject he could fall in with, and occasionally trying his hand at unravelling mysteries by means of his art.

The years 1642 and 1643 were devoted to a careful revision of all his previous reading, and in particular, having lighted on Valentine Naibod's Commentary on Alcabitius, he "seriously studied him and found him to be the profoundest author he ever met with."

Even John Selden seems to have acknowledged him, and probably the chief difference between him and the mass of the community at the time was that, while others believed in the general truth of astrology, he ventured to specify the future events to which he referred.

He came under the lash of Samuel Butler, who, making allowance for some satiric exaggeration, has given in the character of Hudibras' Sidrophel a probably not very incorrect picture of the man; and, having by this time amassed a tolerable fortune, he bought a small estate at Hersham in Surrey, to which he retired, and where he diverted the exercise of his peculiar talents to the practice of medicine.