Girolamo Dalla Casa (born probably c. 1543, exact date unknown – died 1601, Venice) was an Italian instrumentalist, composer and theorist of the late Renaissance Venetian school. A virtuoso cornett player, he and his brothers formed the first permanent instrumental ensemble at St Mark’s Basilica from 1568, working closely alongside Giovanni Gabrieli.

His lasting significance rests on his 1584 treatise on ornamentation, Il vero modo di diminuir, a landmark text on the art of adding virtuosic melodic diminutions to existing vocal works — a technique bridging Renaissance and early Baroque performance practice.

Sources:

• https://en.wikipedia.org/wiki/Girolamo_Dalla_Casa