John Greaves

John Greaves, who lived from 1602 to 1652, was an English mathematician, astronomer and antiquarian. Born at Colemore in Hampshire, he studied at Balliol College, Oxford, became a Fellow of Merton College in 1624 and was chosen Gresham Professor of Geometry in 1630. He travelled in Italy and the Levant from 1636 to 1640, collecting Arabic and Persian manuscripts and an Almagest of Ptolemy, trying to fix the latitude of Alexandria, and making a more accurate survey of the pyramids of Egypt than any earlier traveller. He was a pioneer of metrology through his study of ancient weights and measures. In 1643 he became Savilian professor of astronomy at Oxford, and in 1645 he proposed a reform of the Julian calendar that the king approved but the war prevented. A royalist, he lost his Oxford posts in 1647.