OLDENBURG, Henry, was born in the duchy of Bremen, in Lower Saxony. During the long parliament, he was appointed consul for his countrymen, at London, after the usurpation of Cromwell; but being discharged of that employment, he was appointed tutor to the Lord Henry O'Bryan, an Irish nobleman, whom he attended to the university of Oxford, where he was admitted to study in the Bodleian Library in the beginning of the year 1656. He was afterwards tutor to William Lord Cavendish, and was acquainted with Milton the poet. During his residence at Oxford he became acquainted with the members of that body, which there gave birth to the Royal Society, upon the foundation of which he was elected a fellow; and when the society had found it necessary to have two secretaries, he was chosen as assistant secretary to Dr Wilkins. He applied himself with extraordinary diligence to the business of his office, and in the year 1664 began the publication of the Philosophical Transactions, which he continued to publish to No. xxxvi. 25th June 1677. After this the publication was discontinued till the January following, when it was again resumed by his successor in the office of secretary, Mr Nehemiah Grew, who carried it on till the end of February 1678. Mr Oldenburg died at his house at Charleton, near Greenwich, in Kent, in August 1678.