In music, "BC" primarily refers to basso continuo. This term denotes a foundational element of Western classical music, particularly prominent during the Baroque era (roughly 1600-1750).
Understanding Basso Continuo
Basso continuo, often abbreviated as "bc." or sometimes contextually as "BC," served as the harmonic and rhythmic backbone of much Baroque music. It typically involved two or more instruments working together:
- A bass-line instrument: This instrument plays the lowest written notes, providing the fundamental bass line of the composition.
- A chord-playing instrument: This instrument realizes (improvises) the harmonies above the bass line, filling out the texture.
The primary function of the basso continuo was to provide a continuous, sustained harmonic foundation, allowing other melodic instruments or vocalists to elaborate on top. It gave the music its characteristic richness and forward momentum.
Instrumentation of Basso Continuo
The instruments used for basso continuo could vary depending on the ensemble, the specific piece, and the desired sound. Common pairings typically included one instrument from the "Chordal" column and one from the "Bass" column:
| Role | Common Chordal Instruments | Common Bass Instruments |
|---|---|---|
| Chordal Realization | Harpsichord | Cello |
| Organ (chamber organ) | Violone | |
| Lute | Bassoon | |
| Theorbo | Contrabass (Double Bass) | |
| Guitar | Gamba (Viol) |
Figured Bass and Realization
To guide the chord-playing instrument, composers often used a system called figured bass. This involved placing numbers and symbols above or below the written bass line. These figures indicated the specific chords to be played, but left the exact voicings, inversions, and ornamentation to the discretion of the performer. This allowed for a degree of improvisation and artistic freedom, making each performance of the continuo line unique.
Distinguishing BC in Music from General Usage
It is important to note the distinction between "BC" as a musical abbreviation and its more general historical meaning. While "BC" (without a period) commonly stands for "Before Christ" or "Before Common Era" when referring to historical periods, within the specific context of music terminology and abbreviations, especially when seen as "bc." (with a period), it specifically refers to basso continuo. Therefore, when encountered in a musical score, a scholarly text about music, or a discussion of musical periods, "BC" is most likely referring to this essential Baroque accompaniment.
