From Maria Popova’s Brain Pickings, quoting John D. Barrow’s 100 Essential Things You Didn’t Know You Didn’t Know: Math Explains Your World
“The modern pencil was invented in 1795 by Nicholas-Jacques Conte, a scientist serving in the army of Napoleon Bonaparte. The magic material that was so appropriate for the purpose was the form of pure carbon that we call graphite. It was first discovered in Europe, in Bavaria at the start of the fifteenth century; although the Aztecs had used it as a marker several hundred years earlier. Initially it was believed to be a form of lead and was called ‘plumbago’ or black lead (hence the ‘plumbers’ who mend our lead water-carrying pipes), a misnomer that still echoes in our talk of pencil ‘leads’. It was called graphite only in 1789, using the Greek word ‘graphein’ meaning ‘to write’. Pencil is an older word, derived from the Latin ‘pencillus’, meaning ‘little tail’, to describe the small ink brushes used for writing in the Middle Ages.”
From Wikipedia: Conté invented the modern pencil lead at the request of Lazare Nicolas Marguerite Carnot. The French Republic was at that time under economic blockade and unable to import graphite from Great Britain, the main source of the material. Carnot asked Conté to create a pencil that did not rely on foreign imports. After several days of research, Conté had the idea of mixing powdered graphite with clay and pressing the material between two half-cylinders of wood. Thus was formed the modern pencil. Conté received a patent for the invention in 1795, and formed la Société Conté to make them.