"The Thunderer" is one of John Philip Sousa

John Philip Sousa

John Philip Sousa was an American composer and conductor of the late Romantic era, known particularly for American military and patriotic marches. Because of his mastery of march composition, he is known as "The March King" or the "American March King" due to his British counterpart Kenneth J....

's march

March (music)

A march, as a musical genre, is a piece of music with a strong regular rhythm which in origin was expressly written for marching to and most frequently performed by a military band. In mood, marches range from the moving death march in Wagner's Götterdämmerung to the brisk military marches of John...

es. It was written in 1889.
The origin of the name is not officially known, though it is speculated that it gets its name from the "pyrotechnic [effects] of the drum and bugle in [the] score."
It is also one of his most famous, and easy to perform.

The music

The piece is in much the same manner as most of Sousa's music; however, it is one of his first "distinctly American-sounding marches.". The march follows the standard form (IAABBCDCDC) that is used in many of his other works. As is common, his themes are contrasting. During the repeat of the B section, Sousa introduces new countermelodic ideas. The trio is songlike. There is a ritardando leading into the repeat of the final theme, seguing to the piece's conclusion.