Adelita was composed by the great Spanish composer/guitarist, Francisco Tarrega. Tarrega is my favorite guitar composer and this is one of my favorite pieces by him. I have been playing this for a loooooooong time and I never get tired of it.
Adelita is composed in the style of a Mazurka, which is a type of Polish dance in triple time. Generally the accents fall on the second or third beat. This makes sense for me because I have always felt that Tarrega was inspired by the Polish composer, Chopin.