The book presents a detailed description of all known astrolabes and quadrants made in England in the Middle Age, placing these instruments within their historical context. It analyses the socio-cultural and intellectual situation in England in the Early Middle Ages, which allowed astronomical instrument manufacture to develop and flourish in the fourteenth century. With additional consideration of the political situation in England and northern Europe during this period, including the Black Death and the beginning of the 100 Years War, the text also develops a series of interlocked hypotheses regarding the instruments' makers, owners and commissioners, revealing the influence of English instruments in continental Europe. The tools used to make these instruments are also described: these are largely undated and unsigned, but by reverse-engineering their designs and studying their metallurgy for the first time it is possible to assign likely dates of manufacture. Including seven specialized appendices and an extensive bibliography, the book is a detailed and copiously illustrated catalogue of all surviving Medieval English astrolabes and quadrants placed in their historical, social, and technical context.
