In 1638 Girolamo Fantini wrote eight multi-sectional trumpet sonatas. This dissertation compares these sonatas with recognized stile moderno solo instrumental sonatas by Biagio Marini and Dario Castello in order to show that Fantini’s sonatas are stile moderno trumpet sonatas. This study looks at how form, texture, motivic organization, and instrumental effects function in the works of Castello, Marini, and Fantini. This comparison shows how and to what degree Fantini uses stile moderno characteristics in his works and concludes that Fantini’s sonatas are full-fledged examples of stile moderno trumpet sonatas.