Composed in 1987, this work for a cappella chorus of approximately nine minutes' duration was written on the occasion of the bestowing of an honorary doctorate on the composer by the Universidad Autonoma de Madrid. Penderecki employs four stanzas of the traditional verse attributed to Hrabanus Maurus, and assigns varying numbers of voices within the four overlapping standard ranges (SATB) so that the density of the choral sound is also modulating throughout the piece which proves to be a particularly effective device for creating musical imagery.