While "money notes" are often high notes, in some cases, the hard-to-hit notes are low notes sung by a mezzo-soprano or alto female singer, or low notes sung by a bass-baritone singer. Many of the well-known "money notes" written for the tenor voice are from the "bel canto" era, such as Donizetti's sequence of 9 "C"s above middle C during "La fille du régiment". With Wagner came an emphasis on using the tenor for vocal heft for in protagonist roles, with this vocal category described as "Heldentenor", a heroic-sounding, bold male voice that listeners find to be very dramatic.