Sequentia is an early music ensemble, founded in 1977 by Benjamin Bagby and Barbara Thornton (died 8 November 1998). The group specializes mainly in Medieval music. Sequentia focuses particularly on music with texts, specifically chants and other stories with music, such as the Icelandic Edda. They are interested in the interplay between drama and music, and sometimes do partially staged performances, such as that of Hildegard of Bingen's Ordo Virtutum. Bagby and Thornton have both been active in original research on the projects they perform.