The fourth movement (Adagietto) of Gustav Mahler's 5th Symphony may be his most famous composition and is the most frequently performed of his works. It is said to represent Mahler's love song to his wife Alma.
 
It lasts for approximately 9 minutes, and Mahler's instruction is Sehr langsam (very slowly). It was performed during the funeral Mass for Robert F. Kennedy at St. Patrick's Cathedral, conducted by Leonard Bernstein.
 
Originally scored for strings (only) and harp, it is the contrasting calm movement of the tumultuous 5th Symphony. According to Mahler's own musical instructions, it is meant to be performed with maximum expression and tenderness.

While the harp provides an important color to the intent, this arrangement for brass ensemble was first scored without the harp and can be performed without.