Thomas Greaves (1612-76), orientalist, and John Greaves (1602-52), Savilian Professor of Astronomy at Oxford, were brothers. Though the manuscripts described here were acquired on the death of John Greaves it is almost certain that the oriental material was that of his brother Thomas, who was appointed deputy Professor of Arabic at Oxford, between 1637 and 1641, while Edward Pococke was in the Near East. See the Dictionary of National Biography for further details.
From the guide to the Arabic and Persian manuscripts belonging to brothers Thomas and John Greaves, 13th-17th century, (University of Oxford, Department of Oriental Collections, Bodleian Library)