There are at least 2 artists/groups with the name Sequentia. First is an early music ensemble from Cologne, Germany, and second is a trance music production duo formed by Mark Hoogkamer from The Netherlands and Daniel Garczyk from Germany. Sequentia - Medieval Revival Sequentia is an early music ensemble, started in 1977 by Benjamin Bagby and the late Barbara Thornton. The group specializes mainly in Medieval music. Sequentia focuses particularly on music with texts