"Allegro" is one of the many Italian words that can be placed above a staff on sheet music, to indicate at what tempo a piece should be played. "Allegro" indicates a brisk pace, and for the musician to play the piece brightly. Usually, a tempo marker is given for an entire piece, but sometimes multiple tempo markers can be given throughout a piece.

The "classical symphony" features four separate movements: a sonata, or up-tempo section; an adagio, or slow movement; a minuet, or 3/4 dance section; and another up-tempo piece. This format was developed in the late eighteenth century by composers such as Mozart and Haydn. Nonetheless, despite its typical form, a symphony does not always have to adhere to such a strict format. 

The concertmaster is the leader of the musicians in an orchestra, and in some smaller ensembles takes the place of a conductor in controlling the pace, rhythm, and timing of a piece. The concertmaster is almost always a violinist, and sits in the front row of the orchestra, so the audience can clearly see him or her.

The modern piano was developed from the Baroque harpsichord, which plucked instead of hammered the strings in the soundboard. In the late eighteenth and early nineteenth centuries, particularly fueled by Romantic compositions, the piano was made to both be larger and sound larger. Around this time, the keyboard was expanded to include 88 keys, to give it a full 7 1/3 octaves, where the standard for a piano remains today.

In order to identify which singers can sing which part in classical music, human voices are divided into various parts. The highest, and typically most showy, is the soprano, a category usually reserved for the highest female registers. A soprano is usually the lead part and takes some of the most impressive solo work.

The guitar's rise in popularity took place in the late nineteenth century in Europe and America, largely thanks to a move away from large classical ensembles and more towards parlor music. The guitar's ability to play chords easily and accompany a singer made it become immensely popular, despite its lack of use in classical orchestras.

The guitar, developed in the eighteenth and nineteenth centuries, was structured to be an accompanying instrument instead of a lead instrument. As such, it was created to play chords easily, and was given six strings in closer tuning than the four-stringed violin or cello. Despite its humble origins, the guitar's functionality allowed it to become the main lead instrument in popular music.

A contemporary rival of Mozart, Salieri staged 37 operas in his lifetime, but did not write the Requiem in D Minor. Bach and Handel were a German composers in the early and mid-18th century. Beethoven died in the mid-19th century, and is known for works such as the Moonlight Sonata.