To his supporters he was an "English Merlin"; to his detractors he was a "juggling wizard and imposter". Lilly was born on 1 May 1602 in the small village of Diseworth, Leicestershire; the thatched cottage his family lived in still stands near the village church. It was a substantial house for its time, although Lilly's father, (also called William), struggled with the cost of running his farm. By the time Lilly came to school age, his mother, Alice, complained about the family's back-slidings and decayed estate, yet she determined to give her son the best education the family could afford. Lilly was fortunate in receiving a classical education at the Grammar school of Ashby-de-la-Zouch, under John Brinsley, one of the finest teachers of his time. Brinsley was strict in discipline but advocated encouragement and praise, and by the time Lilly left the school in 1619, he was excellently educated and excelled at Latin. This was to serve him well in his later astrological studies, since almost all astrological textbooks were written in Latin at that time. Lilly's hopes of attending Cambridge University were dashed by his father's increasing poverty. 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 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). Wright was looking for a literate youth to act as his secretary and general servant, and at that time Lilly's father (then in prison for debt) was very happy to be rid of him, considering that since his son was no good around the farm, he was "good for nothing". 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". Lilly received a warm welcome from Gilbert Wright, and worked as his servant until Wright's death in 1627. His biography recounts how, during these seven years, he was happy to perform all manner of menial tasks for his master; how he nursed Gilbert's wife through breast-cancer, until she died of the illness in 1624; how he survived the Great Plague of London in 1625; how his master married again in 1626 (a widow named Ellen Whitehaire), and then settled upon Lilly an annuity of £20 a year, before his death in May 1627.