Final answer:
Euripides' plays were performed during the city Dionysia, which was an annual Athenian festival honoring the god Dionysus, featuring competitions among tragic poets.
Step-by-step explanation:
Euripides' plays were written for the city Dionysia, an annual festival held in favour of Dionysus. The City Dionysia was a significant Athenian festival that involved dramatic competitions, where tragic poets would produce and perform their plays. Euripides, a prominent playwright of the fifth century BCE, was known for tragedies that encouraged his audience to criticize established conventions and to reflect on their own social order. His works often featured philosophical reflections and challenged traditional views of gods and heroes, with a particular focus on the psychological understanding of events and human morality.