The Short

9AllaBreve
The question of what Classical and Romantic composers meant when they used ?, or 2 has caused and continues to
cause confusion for performers. Mozart's renotation of the finale of K. 458 and Mendelssohn's two versions of the
Sommernachtstraum overture 584 make it evident that these two composers, at any rate, did not regard ? as necessarily
indicating a literal doubling of speed, as many theorists stated that it should. Not all theorists, however, saw the
function of ? in the same light, and a variety of apparently contradictory explanations of its significance are found in
eighteenth-and nineteenth-century theoretical writings.
?and ? as indications of metre were direct survivals from the old system of proportional signs. In the fourteenth and
fifteenth centuries? was the sign for tempus imperfecta cum prolatio imperfecta, while ? indicated proportio dupla or diminutio
simplex. Along with other proportional signs, they continued to be used, together with proportions expressed as
fractions, during the sixteenth century. When, during the seventeenth century, the fractions gradually evolved into
modern time signatures, some of the proportional signs were retained with modified meanings. Other signs, such as ?,
? , and , which also continued to be used alongside the system of time signatures in the seventeenth century, are only
very rarely found in the eighteenth century and then, for the most part, in theoretical works. As a rule, ? and ? were
both used to signify a metre in which each bar contained notes to the value of a semibreve (though ? is sometimes
found where bars contain notes to the value of a breve). Already in the sixteenth century there was ambiguity about
whether ? indicated that each note should be twice as fast as it would be if the time signature were ? or whether it
merely indicated that the notes should be somewhat faster than with the other; the
584 See Ch. 8.