The earliest known attempt to develop a complete signed mode of a language which could be used to teach deaf children was by the Abbé de l'Épée, an educator from 18th century France. While the Deaf community already used a sign language (now known as Old French Sign Language), Épée thought it must be primitive, and set about designing a complete visual-gestural system to represent the concepts of religion and law that he wanted to impart to his pupils. His system of "signes méthodiques" (usually known in English as "Methodical Signs") was quite idiosyncratic, and although it wasn't a strict representation of French, its success laid the groundwork for the "signed oral languages" of today. The real proliferation of such systems occurred in the latter half of the 20th century, and by the 1980s manually coded languages were the dominant form of communication used by teachers and interpreters in classrooms with deaf students in many parts of the world. Most sign language "interpreting" seen on television in the 1970s and 1980s would have in fact been a transliteration of an oral language into a manually coded language.