In Line of Ascent, Jake works as a proofreader for this printer, Mathias Schürer, in 1515. Perhaps the quotation marks were Jake’s idea. 🙂
The earliest book discovered in which appeared indicia which may properly be termed marks of quotation was printed in 1516 at Strasbourg, Alsace (then in Germany), by Mathias Schurer. It was “De Vitis Sophistarum” by Flavius Philostratus. The marks consisted of two commas in the left hand margin of each page outside the regular type measure. They were placed at the beginning of each line in which a quoted passage appeared, and were evidently added after the page was set up, because their alignment varies greatly.
☛ Concerning Quotation Marks by Douglas C. McMurtrie, New York: privatly printed, 1934, p. 4. Read the full article here.