The general public views hieroglyphs as "picture-writing". Why does this view persist after Champollion showed that the key to reading hieroglyphs is phonetic? This article argues that this misinterpretation is a historical remnant of the transmission and reception of a single text, the Hieroglyphica of Horapollo. The content of Hieroglyphica is reinterpreted as a conflation of the rebus principle with Egyptian ideas of sound symbolism. The reception of this text in the late Renaissance created the idea of a universal language as an unambiguous pictorial writing system, which has never existed for natural language. Sound