Lucas Holstenius, born Lukas Holste, sometimes called Holstein (1596 – 2 February 1661), was a German Catholic humanist, geographer, historian, and librarian. Life Born at Hamburg in 1596, he studied at the gymnasium of Hamburg, and later at Leiden University, where he was closely acquainted with some of the most famous scholars of the age, including Johannes Meursius, Daniel Heinsius and Philip Cluverius, whom in 1618 he accompanied on his travels in Italy and Sicily, thus giving him a taste for the study of geography. Disappointed at his failure on his return to obtain a post in the gymnasium of his native Hamburg, he left Germany for good. Having spent two years from 1622 in England, at Oxford and London, gathering materials for his Geographi Minores, he then proceeded to Paris. At Paris in 1624, he became librarian to the President de Mesmes, the friend of the scholarly brothers Dupuy, and the correspondent of N. Peiresc. At this time he was converted to Catholicism. He was probably led to take this step from reading the writings on mystical theology of the Greek and Latin Fathers. In 1627 he went to Rome, and through the influence of Peiresc was admitted to the household of Cardinal Francesco Barberini, former papal nuncio and the possessor of the most important private library in Rome. In 1636 he became the cardinal's librarian. Much of Holstenius' collection was deposited in the Biblioteca Angelica in Rome. Finally, under Innocent X, he was placed in charge of the Vatican Library. The popes sent him on various honorable missions, such as bearing the cardinal's hat to the nuncio at Warsaw in 1629, and Alexander VII sent him to Innsbruck to receive the formal abjuration of Protestantism from Christina, former Queen of Sweden. He also acted as intermediary in the conversion of the Danish nobleman, Friedrich, Landgrave of Hessen-Darmstadt and of Christoph, Graf von Rantzau. Mostly, however, he was occupied with his studies. Holstenius formed great projects. He was a man of unwearied industry and immense learning, but he lacked the persistency to carry out the vast literary schemes he had planned. Among them, he desired to correct Philipp Clüver's errors and complete his work; to edit, translate and comment the works of the Neoplatonists; to form a collection of the unedited homilies of the Greek Fathers; to collect inscriptions; to write a critical commentary on the Greek text of