There is some debate over the meaning of the original Elzevir printer’s mark that is still used as Elsevier’s logo today and features an old man standing beneath a vine-entwined elm tree. It is inscribed with the Latin term Non Solus (not alone). The mark, first introduced by Isaac Elzevir (son of Lowys) in 1620, was featured on all Elzevir works from that time forth. That the Elzevir family took pride in their mark is undisputed; what they intended it to mean is less clear. Although most scholars agree that the elm represents the tree of knowledge, they cannot agree on the meaning of the intertwined vine. The Parisian librarian Adry posited in 1806 that the elm tree entwined with the grapevine symbolized the bond between brothers Isaac and Abraham Elzevir and that the old man, a hermit, symbolized the seclusion of study. However, contemporary art historian Lucy Schlüter suggests more persuasively that the old man represents a wise scholar, a philosopher — evoking Erasmus’ image of Socrates sitting under a tree in a rural setting delivering fruitful and inspiring lectures.