Why is it called upper and lower case?

 ..why do we refer to large letters as upper case, and small as lower case? It’s actually a remnant of a past where printing presses had manually set letters. Small letters, which were used the majority of the time, were kept in the lower, easier to access case. Where as large letters were kept in the upper. Why is it called upper and lower case? | Office for Science and Society - McGill University