Since the 1630s, the themes of the works have shifted dramatically: instead of the pastoral tradition and Arcadia, poetry of chivalry, mainly by Ludovico Ariosto and Torquato Tasso, or those drawn from hagiography and Christian commedia dell'arte, are preferred. The latter theme is particularly popular during the 1740s. Opera seria is an Italian term used to describe a type of dramatic composition for voice and instrumental forces that was popular in Italy between 1580 and 1630. These pieces usually deal with serious subjects and use text that can be as long as three acts. They are distinct from later comic operas by the fact that they do not include any spoken dialogue. The first opera seria was written by a German-born composer called Heinrich Ignaz Franz Biber. His one-act work was called "Amadigi di Gaula" and it was composed around 1595. It was very successful and had a considerable influence on later composers. In Italy, this kind of music was called "Germanate" because it was popular among the Germans who were moving into powerful positions in the courts of Europe after the discovery of America. They needed light entertainment and Biber's work fit the bill perfectly.