Final answer:
Ancient Greek poetry that was sung on stage is known as dithyrambs, performed during Dionysian festivals and instrumental in the development of classical Greek theater.
Step-by-step explanation:
A type of poetry that was sung on stage in Ancient Greece is called dithyrambs. These were passionate hymns performed by a chorus in honor of Dionysus during the Dionysian festivals such as the City Dionysia. Over time, Greek writers started scripting these performances, leading to the creation of classical Greek tragedies and comedies, which featured not just poetry and song but also dance, props, and costumes to tell stories of gods, heroes, and philosophical themes.
Notably, the inclusion of the Chorus as a group of performers singing or chanting was a significant feature of Greek drama that evolved from earlier Dionysian rituals. This cultural innovation was instrumental in shaping Western literature and had a profound impact on future generations, influencing playwrights such as William Shakespeare and leaving a lasting legacy on the world of theater.