Les Diagonales de Moissac

Les Diagonales de Moissac: at the heart of medieval musical heritage

Nestled in one of the most important sites of Romanesque art in France, the Diagonales de Moissac are more than just an ancient music festival. They represent a unique intellectual and spiritual adventure, driven by CIRMA-Organum and its founder Marcel Pérès, an internationally renowned conductor and musicologist recognized for his pioneering work on the oldest repertoires of Western polyphony.

The Abbatiale Saint-Pierre de Moissac, a masterpiece of Romanesque art with a sculpted portal listed as a UNESCO World Heritage site, provides the ideal setting for these encounters. Its exceptional acoustics, historical significance, and architectural beauty create the conditions for total immersion in the world of medieval chants that resonated there for centuries.

Three sessions per year: spring, summer, autumn

The uniqueness of the Diagonales lies in its seasonal rhythm. Unlike most festivals that focus on a specific period of the year, the Diagonales offer three distinct sessions — spring, summer, and autumn — each centered on a specific repertoire or musical theme:

• Spring Diagonales (May): The spring sessions often explore the oldest repertoires, those at the crossroads of late Antiquity and the early Middle Ages. Marcel Pérès conducts research on the earliest evidence of polyphony, Byzantine chants, and the traditions of Saint-Martial de Limoges.
• Summer Diagonales (July-August): The summer sessions often offer a broader program, with intensive multi-day workshops combining theoretical courses, practical workshops, and public concerts. The repertoire covers the vast chronological arc from Carolingian music to late Gregorian chant.
• Autumn Diagonales (October): The autumn sessions generally tackle more elaborate polyphonic repertoires. Autumn 2026 will be dedicated to the 72 verses for Saint Martial by Adémar de Chabannes, described by Marcel Pérès as “the oldest evidence of Western polyphony.”

Workshops open to all levels

One of the great strengths of the Diagonales is its openness to participants of all levels. The workshops, led by Marcel Pérès himself, welcome professional musicians and researchers as well as passionate amateurs who do not necessarily have formal musical training. What matters is commitment, curiosity, and a willingness to explore sound worlds profoundly alien to our contemporary ears.

As Marcel Pérès says: “It is not simply a matter of taking a score and playing it; one must understand the world to which this music refers.” This intellectual and artistic requirement makes the Diagonales an exceptional place of learning, where medieval music is approached in its historical, theological, and aesthetic complexity.

Ensemble Organum: a global reference

CIRMA-Organum is the structure that supports the Diagonales and, more broadly, the work of Ensemble Organum founded by Marcel Pérès. This ensemble is now recognized as one of the world's leading references for the interpretation of medieval repertoires. Their recordings for Harmonia Mundi have revealed musical treasures long ignored to the general public.

In Moissac, this living heritage finds its natural anchor. The Benedictine abbey of Moissac, founded in the 7th century, was one of the great cultural and religious centers of the Middle Ages. It is there, in this place steeped in memory, that ancient chants regain their breath and meaning.