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. Travels in the Levant In 1637 he made a journey to the Levant, one 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