Yes, mandolins go "way back" in European music. But because they are so portable, and Americans are so mobile, mandolins have played a big role in American music as well. You see photos of them in mining camps, in Civil War photos, on the Western frontier.
What you may not know was that in the 1890s-1910s, mandolin was as popular in American homes as guitars in the 1960s. There were even mandolin orchestras, community "string bands" of a sort, based around the instrument.
The fact that mandolin is tuned the same as violin has also made it a favorite "doubling" instrument for fiddlers of all kinds, especially Bluegrass and Celtic. The Irish banjo, in turn, benefits by being tuned an octave down from the mandolin, as are several mandolin-type instruments.
I'm a latecomer to the instrument myself, so I generally use adapted guitar patterns on the thing. And I've never owned a pro mandolin (or deserved to own one, really). But I appreciate its role in American music of all kinds. Anything you have to share about the instrument can go in this forum. Just hit "New Topic" or "Post Reply" depending where you want to take the discussion.