Dates in Art History

Dates seem a little confusing between the textbook and the Web sites.  The book says the National Academy of Design opened in 1826.  The Web site says the school opened in 1926, but the academy was 1925.  I guess after reading the book, I didn't realize the distinction between the school and the academy.  I kind of thought they were the same. 
I believe you have to seek out all sorts of sources when studying history, because with each source you gain a little more perspective.  My father always said the one who…