St. Mark, shown in a French Renaissance Book of Hours as a scribe who has been cutting his quill with a penknife and is now checking the tip before dipping it in his ink bottle
Waddesdon Manor, Aylesbury, The National Trust. Ms 20, f. 13v. After Christopher De Hamel, Medieval Craftsmen. Scribes and Illuminators (London: British Museum Press, 1992),  pic. 22, p. 28.