AAIDD historical terms defined

The American Association on Intellectual and Developmental Disabilities (AAIDD) is the oldest disability organization in the United States, with its inception dating 125 years ago. Since that time, many, many terms have been use to describe persons with mental retardation.
What are a few terms that been used historically?
Would terminology history is link with the naming difficulties for this student and adult population?
Why is intellectual disability a popular term in the organization versus the term mental retardation