was sung in plainchant. Each movement states the structural melody twice through, and always in the tenor. It is stylistically close enough to the work of John Dunstaple that it has been suggested that it may be his work, but no actual link has been found. The most significant feature of the mass for the development of music on the continent was its freely composed bass line. The possibilities must have been obvious to composers, since many immediately imitated the procedure, which allowed for harmonic freedom unchained to the tenor, a voice which formerly inhabited the lowest range alone. Freely composed, the bass could control harmony in a way that made possible the chord progressions and gradual shift to functional tonality that took place a hundred years later. The late 15th century was to see an outpouring of music exploiting low tessituras, for example in the output of Johannes Ockeghem, an innovation which began with the Missa Caput. Possible symbolism Another of the mysteries of the Missa Caput, which became especially prominent after the source of the cantus firmus was discovered, was why an elaborate polyphonic composition would have been written for a time in the liturgical calendar which generally avoided polyphonic musical display. Little music was written in an elaborate manner for any events during the Lenten season, and Maundy Thursday was the most mournful of all the days in that period. One suggestion is that the symbolism of the Caput ("head" in Latin) has not been taken into account, and while the Sarum Rite chant melisma may have been used as the source, the mass was used for an entirely different purpose, one perhaps based on this symbolism. Suggestions for this center around the symbolic meaning of "head". Following is the Latin from the end of the Sarum antiphon, Venit ad Petrum, with its English translation (KJV): ...domine non tantum pedes meos sed et manus et caput." "[Simon Peter saith unto him], Lord not my feet only, but also my hands and my head." In the fifteenth century, a common motif in religious iconography was the crushing of the head of the serpent, as seen in illustrations of Saint George and the Dragon. Celebrating this victory may have been one of the intents of the Missa Caput. In addition, numerous illustrations and documents show the Virgin crushing the head of the serpent herself: this could establish the connection