The Glaswegian vocal quartet iuchair (Scot Gaelic for key) will open the festival weekend with a concert centred on Guillaume de Machaut’s Messe de Nostre Dame, and give audiences a comprehensive picture of music in France during the 14th century. In a bold choice, the programme will also pair Machaut’s masterpiece with Francis Poulenc’s Quatre petites prières de Saint François d’Assise.

It may seem difficult to imagine two more diametrically opposed pieces than these, separated as they are by half a millennium and completely different musical languages. Yet despite their differences, there are certain parallels that could be drawn between the sometimes stark and chaotic counterpoint of Machaut, and the harmonic language of Poulenc that moves from sweet to sour at a moment’s notice.