Since 1883, “Semper Fidelis” (always faithful) has been the motto of the United States Marine Corps, and in 1888 John Philip Sousa, conductor of the Marine Corps Band, wrote this march with the same name. Note: in this exercise the occasional parenthesized note is a substitution to keep the piece within the simple diatonic scale.
https://en.wikipedia.org/wiki/Semper_Fidelis_(march)