When musicological research fails from the outset because it finds the deed but not the slightest clue as to the perpetrator, then we have to surrender completely to the listening experience and forget the unknowns. This is also the case with Missa solennis, which a certain Ioannes Cuisean composed for the people of Cologne as commissioned for the Feast of St Gereon in 1663. Did the composer have something to do with the Strasbourg Cathedral because the only copy of the work survived there? No one knows. This has motivated the Cologne-based Josquin Capella, which celebrates its 30th anniversary in 2024, to make a grand event of this piece, which is as enigmatic as it is beautiful. Framed and interspersed with organ pieces by his – anything but unknown – contemporary Johann Jacob Froberger (1616-1667), a liturgy of magnificent sound is created with no need for further "research".