The Mathematical Jewel, published in 1585, introduced an advanced universal astrolabe design that solidified John Blagrave's reputation as a significant Tudor-era mathematician and instrument creator. Born in Earley in 1561, his work bridged the gap between theoretical calculations and practical navigation, cementing his place in the history of English astronomical science during the late sixteenth century.
Education and Background
Blagrave was born into the landed gentry of Berkshire. He attended Reading School before continuing his studies at St John's College, Oxford. Although he focused heavily on mathematics during his time at the university, he did not complete a formal degree. His family connections were significant; his father, John Blagrave of Bullmarsh, provided him with a ninety-nine-year lease on Southcote lands in 1591. He married Dorothy Gunter, a widow from Wiltshire, and took on responsibility for his step-daughter, Jane.
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Blagrave authored five distinct works and produced a sheet map of the Northern Hemisphere. His most prominent publication, The Mathematical Jewel, detailed an astrolabe featuring four movable parts: the Mater, Rete, Label, and Rule. These components allowed for complex calculations involving navigation, trigonometry, and astrology. His subsequent work, The art of dyalling, provided early instructions on sundial construction. Other notable titles include the 1590 Baculum Familliare, which detailed his invention of the Familiar Staff, and the 1596 Astrolabium Uranicum generale.
Legacy and Philanthropy
Following his death on 9 August 1611 at Southcot Lodge, Blagrave was buried at the Church of St. Laurence in Reading. His will reflected both his mathematical obsession and a commitment to local charity. He commissioned a funeral monument featuring a bust and allegorical figures, crafted by Gerard Christmas. His charitable bequests included funds for the poor and servants, as well as an unusual lottery system. This lottery, held on Good Friday, provided an annual cash prize to unmarried maidservants of good character who had served a single master for five years, a tradition that persisted into the nineteenth century.
Fast facts
- Born: 1561, Earley
- Died: 9 August 1611, Reading
- Education: Reading School, St John's College, Oxford
- Burial Site: Church of St. Laurence, Reading
- Primary Field: Mathematics and Astronomy
- Key Publication: The Mathematical Jewel (1585)
- Spouse: Dorothy Gunter
Questions readers ask
Did John Blagrave have any children?
He had no children of his own, though he was the step-father to Jane, the daughter of his wife, Dorothy Gunter.
Where is his monument located?
It is located at the Church of St. Laurence in Reading, near the site where he was buried.
