An obligato is a piece of music that the composer considers to be extremely important. When the note “obligato” or “obbligato” appears in a musical composition, it indicates that the marked section should not be skipped or changed because it is essential to the piece. A marking used to indicate that the relevant section can be altered or left out to suit the needs of the performer or conductor is ad libitum, which is the polar opposite of obligato or “obligatory.”
The word obligare comes from the Latin word obligare, which means “to bind.” Many musicians prefer the spelling obbligato, which is written in Italian, but “obligato” is also acceptable, especially among English-speaking musicians and composers. An obligatory section of a composition is not negotiable, as the term suggests.
Composers who wanted to keep certain parts of their works intact had to use obligato notation because musicians often adapted, changed, or left out chunks of music in the past. While this may seem strange to modern music fans, this practice was once quite common, especially since classical music is often performed as written today. Depending on the piece, the term may also serve as a firm reminder that the music is not only necessary, but that it should also be performed exactly as written, on the instrument for which it was written.
It is common to see markings that distinguish between obligato and basso continuo, especially in Baroque compositions. A basso continuo is typically intended to be an unobtrusive accompaniment to the piece’s main melody, and it is frequently improvised by the musician in performance. When a musician uses an obligato notation, it means that he or she has a specific vision for the harmonic accompaniment and wants musicians to follow it.
The meaning of the term “obligato” has shifted in some circles as the trend of modifying classical music as desired has faded. In some cases, the term is used in the opposite sense of its original meaning, to designate a section of a composition that is unnecessary or unimportant. For musicians who do not feel up to the original composition, a composer might provide an obligatory alternative to a difficult section in a piece of music. Needless to say, this is perplexing, and some classical performers and composers find it irritating.