A phenomenon where a historical (or otherwise original) figure gets overshadowed by its version from modern culture. Named after Astolfo, who is originally a character from a
French legend, but most people nowadays know him from the Fate
anime franchise as the
guy who looks like a girl, also referred to as trap or femboy.
Most prominent if you try to look their images up. There are even more famous examples, such as the infamous dictator Nero Claudius.