Period (music)

In music, a period is a group of phrases consisting usually of at least one antecedent phrase and one consequent phrase totaling about 8 measures in length (though this varies depending on meter and tempo). Generally, the antecedent ends in a weaker and the consequent in a stronger cadence; often, the antecedent ends in a half cadence while the consequent ends in an authentic cadence. Frequently, the consequent strongly parallels the antecedent, even sharing most of the material save the final measures. In other cases, the consequent may differ greatly (for example, the period in the beginning of the second movement of the Pathetique Sonata).

The 1958 Encyclopédie Fasquelle defines a period as follows:

• "A complex phrase, in which the various parts are enchained."

Another definition is as follows:

• "In traditional music...a group of bars comprising a natural division of the melody; usually regarded as comprising two or more contrasting or complementary phrases and ending with a cadence." (Harvard Dictionary of Music, 1969)

And

• "A period is a structure of two consecutive phrases, often built of similar or parallel melodic material, in which the first phrase gives the impression of asking a question which is answered by the second phrase."

A double period is, "a group of at least four phrases...in which the first two phrases form the antecedent and the third and fourth phrases together form the consequent."