Leo Kanner was the person who, in the early 1940's, first defined autism in English. He described what is now commonly known as "classic" or "low-functioning" autism which includes many of the most common stereotypes of what autism is. Around the same time, Hans Asperger, a German, described what is now known as Asperger Syndrome or High Functioning Autism. Asperger's writings were not translated into English until quite recently.