He was born in Colemore, near Alresford, Hampshire. He was the eldest son of John Greaves, rector of Colemore, and Sarah Greaves. His brothers were Nicholas Greaves, Thomas Greaves and Sir Edward Greaves, physician to Charles II.
His father ran a school for sons of the neighbouring gentry, where Greaves began his education. Aged 15, he went to Balliol College, Oxford between 1617–1621, gaining a B.A. degree. In 1624 he was the first of five newly elected Fellows of Merton College, becoming M.A. in 1628. He began to study astronomy and oriental languages, and especially the works of the ancient eastern astronomers. In 1630 Greaves was chosen professor of geometry at Gresham College, London. Through his predecessor, Peter Turner, he later met archbishop William Laud, the chancellor of Oxford University and Visitor (patron) of Merton College. Laud was keen to make English editions of Greek and Arabic authors, and Greaves' later travels abroad involved collecting manuscripts and books for presentation to his new patron.
Greaves enrolled at University of Leyden in 1633, where he became friends with Jacob Golius, professor of Arabic at Leyden. He enrolled at the University of Padua in 1635 along with George Ent, meeting the Dane Johan Rode (John Rhodius), an expert on ancient weights and measures, who also made a commentary on Celsus. A brief return to England was followed by a second European journey; in 1636 he sailed via Livorno (Leghorn) to Rome, dining with Ent on 5 October at the English College, Rome; he also met William Harvey, who was entertained at the College on the 12th, Gasparo Berti, Lucas Holstenius and Athanasius Kircher. Probably in the same month he met and consulted with the Earl of Arundel's art-collecting agent, William Petty (who dined at the College on 14 October), on the Earl's attempted acquisition of the Obelisk of Domitian, then still lying broken in the Circus of Maxentius. Though 'now it is broken into 5 stones' he measured these and including a sketch of the obelisk as hypothetically repaired in his almanac-notebook (Bodleian Library Savile MS 49,1). Though Arundel paid a 60 crown deposit for the obelisk, pope Urban VIII vetoed its export and it was erected by his successor Innocent X above Bernini's Fountain of the Four Rivers in the Piazza Navona.
Greaves toured the Catacombs and made drawings of the Pantheon and Pyramid of Cestius. During his stay in Rome he instituted inquiries into the ancient weights and measures that are among the early classics of metrology.
In 1637 he made a journey to the Levant, one (unfulfilled) intention being to fix the latitude of Alexandria where Ptolemy had made his astronomical observations. He sailed from England to Livorno in the company of Edward Pococke; after a brief visit to Rome, he arrived in Istanbul (Constantinople) around April 1638. There he made the acquaintance of the English ambassador Sir Peter Wyche. He procured various manuscripts there, including a copy of Ptolemy's Almagest ("the fairest work I ever saw"). Greaves ended up owning two copies of the Almagest. He was going to have visited the many monastic libraries at Mount Athos, in order to make a catalogue of their MSS and unprinted books. Athos was normally open only to members of the Orthodox church, but thanks to a special dispensation from the Patriarch of Constantinople Cyril Lucaris, Greaves would have had access; but the execution of the patriarch by strangulation in June 1638 for treason against Sultan Murad IV prevented his journey.
Instead, Greaves continued on to Alexandria, where he collected a number of Arabic, Persian and Greek manuscripts. He was an inveterate note-taker, making countless observations in notebooks and on blank pages of other books he bought; he also visited Cairo twice, and made a more accurate survey of the pyramids of Egypt than any traveller who had preceded him. He returned to England in 1640.
On the death of John Bainbridge in 1643, Greaves was appointed as Savilian professor of astronomy and senior reader of the Linacre lecture at Oxford; but he was deprived of his Gresham professorship for having neglected its duties. In 1645 he essayed a reformation of the calendar; but although his plan of omitting the bissextile day (29 February) for the next 40 years was approved by the king, the matter was dropped owing to the turbulent times.
Ejection from Oxford
In 1642 Greaves had been elected subwarden of Merton College. Merton was the only Oxford college to side with the Parliamentarians in the English Civil War, through an earlier dispute in 1638 between Nathaniel Brent, the Warden of Merton, and Greaves' patron William Laud. Brent had been a hostile witness at Laud's 1644 trial. After Laud was executed on 10 January 1645, Greaves drew up a petition for Brent's removal from office; Brent was deposed by Charles I on 27 January.
However, in 1647 a parliamentary commission (visitation) was set up by Parliament "for the correction of offences, abuses, and disorders" in the University of Oxford. Nathaniel Brent was the president of the visitors. After Thomas Fairfax had captured Oxford for the Parliamentarians in 1648 and Brent had returned from London, Greaves was accused of sequestrating the college's plate and funds for king Charles. Despite a deposition from his brother Thomas, Greaves had lost both his Merton fellowship and his Savilian chair by 9 November 1648. Many of his books and MSS disappeared after his rooms were rifled by soldiers, although his friend John Selden managed to recover some of them. However, Greaves was not actually deprived of the professorship until August 1649. He was succeeded as Savilian Professor of Astronomy in that year by Seth Ward, who ensured that Greaves was paid the arrears (£500) of his salary; Greaves was unlikely to have got his money, since the Savilian professors were paid from the income of lands held in Kent and Essex, which were under control of Parliament (rather than the king). Ward also gave over a considerable amount of his own salary to Greaves.
But Greaves' private fortune more than sufficed for all his wants till his death; he retired to London, married and occupied his leisure writing and editing books and manuscripts. He died in London aged 50, and was buried in the church of St Benet Sherehog, which was destroyed during the Great Fire of London.
His brother Nicholas Greaves was his executor. He left his cabinet containing his coin collection to Sir John Marsham, and his astronomical instruments to the university, for the use of the Savilian professors. Two of his astrolabes (inscribed by his brother Nicholas) are in the Museum of the History of Science, Oxford. (see External links)
Besides his papers in the Philosophical Transactions, the principal works of Greaves are:
- Pyramidographia, or a Description of the Pyramids in Ægypt (1646)
- A Discourse on the Roman Foot and Denarius (1647)
- Elementa Linguae Persicae (1649)
The first two above works were reprinted (together with a biographical notice of the author) as part of
- Greaves, John (1737) Miscellaneous works of Mr. John Greaves Vol. I and Vol. II. London: Published by Dr Thomas Birch, printed by J. Hughes for J. Brindley and C. Corbett. This also contains a reprint of
- Withers, Robert (ed. John Greaves) A Description of the Grand Signour’s Seraglio; or Turkish Emperours Court (1653) London: Printed for Jo. Ridley, at the Castle in Fleet-street by Ram-Alley.
- Chorasmiae et Mawaralnahrae, etc. (1650). A description of Khwarezm and Mawarannahr (Transoxiana) translated from the Arabic of Abu'l-Fida, with tables of latitude and longitude for the principal towns.
- Abulfedae Peninsulam Arabum. This is an edited translation of part of Abu'l-Fida's History.
- Binae Tabulae Geographicae, two tables of latitude and longitude translated from the Persian of Nasir al-Din al-Tusi and Ulugh Beg
The above three works appeared in Hudson, John (1712): Geographiae Veteris Scriptores Graeci Minores Vol. III, Oxon. (in Latin)
- Lemmata Archimedis, apud Graecos et Latinos iam pridem desiderata, e vetusto codice manuscripto Arabico... This is a translation of part of Nasir al-Din al-Tusi's edition of the so-called Middle Books. Greaves' unpublished MS was revised and amended by Samuel Foster and appeared posthumously in 1659.
- Foster, Samuel (1659). Miscellanea sive lucubrationes mathematicae. London: printed by R. & W. Leybourn, published by John Twysden.
The following book is probably not by John Greaves, although his name appears on the title-page:
- Greaves, John. The origin and antiquity of our English weights and measures discover'd... (Google books 1745 edition) London: Printed for G. Sawbridge. This book, thrice printed in 1706, 1727 and 1745, discusses Greaves' findings and measurements: but it appears to be the work of another hand.
- Shalev, Zur (2005). The travel notebooks of John Greaves in Intersections: Yearbook for early modern studies Vol. 5, 2005. Leiden: Koninklijke Brill NV.
- Macquorn Rankine, W. J. in Imperial Dictionary of Universal Biography Vol II, p.713 London: William Mackenzie
- Birch, Thomas (1737). Miscellaneous works of Mr. John Greaves. London: J. Brindley and C. Corbett. p. i–lxxii. Retrieved 6 May 2011.
- Edward Chaney, "Roma Britannica and the Cultural Memory of Egypt: Lord Arundel and the Obelisk of Domitian", in Roma Britannica: Art Patronage and Cultural Exchange in Eighteenth-Century Rome, eds. D. Marshall, K. Wolfe and S. Russell, British School at Rome, 2011, pp. 147–70, fig. 11.11.
- Greaves, John (1647); A Discourse on the Roman Foot and Denarius London: Wm Lee. p.47
- Dictionary of National Biography, article on Brent, Sir Nathaniel, pp. 262–4
- Ward, John (1740). The Lives of the Professors of Gresham College, to which is prefixed the Life of the Founder, Sir Thomas Gresham, pp. 144–146 London: John Moore. Google Books full view, retrieved 10 May 2011
- Twells, Leonard (1816). The Lives of Dr. Edward Pocock: the celebrated orientalist, Volume 1. London: Printed for F.C. and J. Rivington, by R. and R. Gilbert. p. 123. Retrieved 13 May 2011.
- Pope, Walter (1697). The Life of Seth Ward, Lord Bishop of Salisbury. London: Wm. Keeblewhite. pp. 18–21. Retrieved 11 May 2011.
- Abstracts of probate acts in the Prerogative court of Canterbury (Volume 6). Will proved 19th? October 1652.
- Smith, Thomas (1707) (in Latin). Vita quorundam eruditissimorum virorum. London: David Mortier, at the sign of Erasmus, p.34.
- Hogendijk, Jan P. (2008). "Two Beautiful Geometrical Theorems by Abū Sahl Kūhī in a 17th Century Dutch Translation" (PDF). Tārīkh-e ‛Elm: Iranian Journal for the History of Science (History of Science Institute of the University of Tehran) 6: 1–36. Retrieved 8 August 2011.
- This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). Encyclopædia Britannica (11th ed.). Cambridge University Press
- Measurer of all things: John Greaves – The great Pyramid and early Modern Metrology by Zur Shalev
- Astrolabe belonging to John Greaves, inscribed by Nicholas Greaves.
- Large astrolabe originally made for Queen Elizabeth I, Museum of the History of Science, Oxford