In 1840, the Danish artist Christian Albrecht Jensen (1792–1870) was commissioned to paint a portrait of the renowned mathematician Carl Friedrich Gauss (1777–1855). This portrait, showing Gauss at the venerable age of 63, went on display at the Pulkowa Observatory in St. Petersburg, Russia, where it remains to this day.
That painting of Gauss has been copied many times over the years, with variants of the portrait even appearing on bank notes and postage stamps.