 Lipsius saw to the publication of his own letters, bringing out three collections or Centuriae (since each contained 100 epistles), in his lifetime, the first of which appeared in Leiden in 1586. He prepared another Centuria for posthumous publication by his executor Joannes Woverius, who, together with his fellow-executors, added a fifth Centuria postuma. From this vast correspondence, it is apparent that Lipsius was a central figure in the Republic of Letters of his day, renowned for his philological skills, his historical knowledge and his search for a new type of humanitas (civilized and humane conduct) suited to the troubled times in which he lived. The inventory of Lipsius’s letters includes more than 4,300 items and 700 correspondents, among them not only Montaigne, but also such distinguished scholars as Isaac Casaubon, Henri Estienne, Joseph Scaliger, Sir Philip Sidney, Paolo Manuzio, Fulvio Orsini, Joannes Sambucus, Joachim Camerarius, Benito Arias Montano, Francisco de Quevedo, Abraham Ortelius, Hugo Grotius, and Philip Rubens, brother of the artist Peter Paul, who immortalized Lipsius in his painting The Four Philosophers (now in the Palazzo Pitti in Florence). Most of the letters reflect Lipsius’s friendships, thoughts, feelings, teachings and attempts at self-presentation. Yet his letter collections were also meant as an extension of his humanist scholarship and his Neostoic intellectual program.