Question $1(2\mathrm{.}5$ points$)$

A highly expressive example of Gregorian chant in the late Middle Ages is $O$ successores by the nun Hildegard of Bingen $(1098-1179),$ abbess of Rupertsberg in Germany. The chant was composed to be sung by the nuns in Hildegard's convent; it is notated as a single melodic line, without accompaniment. Some performances add a drone instrument which plays one or more very long sustained notes as the chant melody is sung. Our performance uses a portative organ, a small portable medieval pipe organ.

The Latin text of the chant is below with an English translation:

The women's choir simes throubhout the cntre work but the drone instrument stops playing half way through.

Both the women's choir and the drone instrument sing and play throughout the entire work.

A male singer joins the group of singers near the cnd of the work.