What is the name of the first complete opera and who composed it?

The first complete opera is "L'Orfeo," composed by Claudio Monteverdi. Premiering in 1607, it is regarded as a pivotal work in the transition from Renaissance to Baroque music, marking the establishment of the operatic genre. Monteverdi's innovative approach included the use of recitative and arias, which laid the groundwork for the development of opera as a dramatic art form.

"L'Orfeo" tells the mythological story of Orpheus, who travels to the underworld to retrieve his beloved Eurydice, and it incorporates a rich blend of music, staging, and poetic text. Monteverdi's work represents a significant artistic achievement because it fully realized the potential of music to convey dramatic narrative and emotions, setting a standard for future composers. This foundational role in the history of opera underscores the importance of "L'Orfeo" as more than just an entertainment piece; it is a landmark that defined the genre's structure and emotional depth.