Madonna and Child with Saints Petronius and John the Evangelist

On 14 December 1625 the archconfraternity of the Bolognese in Rome, the brotherhood of people from Bologna living in the city, commissioned this altarpiece for the high altar of their church, dedicated to Saint John the Evangelist and Saint Petronius. Domenichino, born in Bologna himself, had put his own name forward and agreed to 200 scudi. The picture was set up on a new marble altar in time for the feast of Saint John at the end of 1629.

The whole picture speaks of Bologna. The Virgin and Child sit on a high base bearing the city's coat of arms and turn toward Saint Petronius, Bologna's patron saint, standing on the right, while John the Evangelist kneels and looks up to heaven. Around the throne, angels play a harp, a cornett, a violin and a viola da gamba, painted precisely enough to be read as real instruments. Together they make up a sonata a tre, a new kind of instrumental music for two solo melodies over a bass, then in fashion in Italy and above all in Bologna. The Bolognese biographer Carlo Cesare Malvasia wrote that Domenichino understood music from its foundations. The sculptor Alessandro Algardi, another Bolognese in Rome, admired the angels' expressions but wondered what they had to do with the subject.