Running away from the plague in London, he spent a year in the countryside to study, reflect, and write Christian Astrology.
[1] Lilly himself explains that he was influenced among others by Ptolemy's Quadripartitum (Tetrabiblos), De occulta philosophia by Agrippa, De Astronima Tractarus 10 by Guido Bonatti, 120 Aphorismi of John Dee, Medicina Catholica by Robert Fludd, Epitomes Astronomiae by Johan Kepler and Paracelsus' De Meteoris, all of which are mentioned in the appendix of Christian Astrology.
Topics covered: This part of Lilly's work is a methodical instruction the student must follow to be able to answer all kinds of questions - on disease, wealth, marriage choices, travel, etc.
In this third part, "How to judge upon Nativities" William Lilly discusses the interpretation of the natal chart.
His treatment includes the following topics: In addition, he also gives clues about how these techniques can be used to 'correct' a natal chart in case the time of birth is not exactly known to the astrologer.