The cathedral of Tournai in Belgium is one of the most impressive and significant in Europe and has been designated by UNESCO as a World Cultural Heritage. Music history was written here: the cathedral library contains the manuscript of a polyphonic mass ordinary compiled around the year 1300 which unites movements by various composers and written in different styles. This makes it the direct predecessor of the first masses written by single composers, such as the Messe de Nostre Dame by Guillaume de Machaut. René Clemencic, the great music researcher and interpreter of medieval music, performs the Messe de Tournai along with additional one voice and polyphonic pieces from the Spanish Codex Musical de las Huelgas.