The lineup of Sequentia changes according to the needs of each particular program. The core consisted of singer and harpist Benjamin Bagby, and singer Barbara Thornton until Thornton's untimely death in 1998; other core members have included medieval fiddlers Margriet Tindemans and Elizabeth Gaver, and singer Suzanne Norin. Groups of singers, most of them international soloists in their own right, comprise Vox Feminae and Sons of Thunder, the women's and men's ensembles of Sequentia. These two sub-groups meet intensively each year in Cologne and Boston, leading workshops and preparing for the current tour/recording project. Since their inception, Sequentia has incorporated instrumental performance, including a panoply of handcrafted replicas of stringed instruments appropriate to their repertoire. Among the many musical repertoires brought to life by Sequentia is that of Hildegard of Bingen, who they have consistently featured. Along with Christopher Page's ensemble Gothic Voices, Sequentia can take credit for the resurgence of interest in Hildegard's music, beginning with their 1982 recording of her passionate morality play, the Ordo Virtutem. More recently, Sequentia produced a series of recordings encompassing Hildegard's complete works, culminating in a new production of Ordo Virtutem in 1998, the 900th anniversary of her birth. Other repertories in their catalog include the music of Philipe de Vitry, a series of Medieval Spanish music, and a reclamation of Medieval Nordic music, including the Icelandic Edda cycles and Benjamin Bagby's solo recitation of Beowulf, and The Rheingold Curse, based on the Icelandic Edda. A recurring motif is their focus on the oral tradition underlying the music they approach; this leads to a stress on texts, linguistics, original notation, and improvisation within understood guidelines.
Each project begins with thorough and often creative scholarship, covering all aspects of linguistics, notation, musical analysis, and performance practices. For example, the Edda project began with Bagby's intensive study of the medieval Icelandic texts as well as current methods of Icelandic folk epic recitation, and research by Gaver into the Hardinger-fiddle tradition. At all times, their goal has been to reach and deeply internalize a contemporary understanding of the modal character of the repertoire, seeing melodies more as constellations of orally-transmitted modal gestures than as linear events. This internalization informs Sequentia's vocal performance, and, more importantly, the character of their instrumental improvisations. The ensemble is known for its characteristic full-voiced, open-throated singing, with evocative shaping of the texts.