The Ten National Airs with Variations for Flute and Piano Opus 107 were composed by Ludwig van Beethoven from 1818 and 1819. Beethoven wrote this piece based on folk-derived melodies. This is one of several sets of pieces that Beethoven wrote that are folk-derived. The piece was for George Thomson, with whom he had a difficult business relationship, a wealthy Edinburgh-based publisher. These variation sets were first published in 1819 in both London and Vienna.
The first of the ten sets of variations uses an Alpine air (E flat), "Ich bin a Tiroler Bua".
The next piece uses the Scottish "Bonny Laddie, Highland Laddie" 
No. 3 utilizes "Volkslied aus Kleinrussland," a Russian dance, as the main theme.
The fourth item employs the popular "St. Patrick's Day." 
No. 5 ("A Madel, ja a madel") includes great difficulty for both instruments.
The Sixth resembles (in mood) to the composer's Sixth Symphony ("Pastoral").
The composer returns to the world of the third piece in No. 7, using a widely-known Russian tune from "Schöne Minka."  The next set may rival the First in quality. The five variations on "O Mary, at thy Window be" are solidly conceived and quite inventive.
The last two sets are based on a Scottish tune ("O, Thou art the Lad of my Heart") and a march, "The Highland Watch." 
^ a b c d e f g h i j k l m http://www.classicalarchives.com/work/117082.html#tvf=tracks&tv=about>
^ Thomson, George in New Grove, 2nd Ed., by David Johnson and Kirsteen C. McCue, V. 25, p. 420
Ten National Airs with Variations for Flute and Piano: Free scores at the International Music Score Library Project.