Socrates's teachings are the focal point of Plato's dialogues; the other speeches in the Symposium arguably serve as foils to Socrates's longer and more systematic discussion of love. Unlike the other men at the gathering, Socrates is largely uninterested in sex and prefers to view love as a collaborative striving after goodness. This frustrates Alcibiades, who sees Socrates as merely playing hard to get.
Diotima of Mantinea is a priestess whose ideas on love form the basis of Socrates's speech. In her view, love is a kind of ladder that progresses from the merely physical to the contemplation of pure, abstract beauty. The passage in which this concept appears is among the most widely discussed in the Symposium. Apart from her appearance in Plato's dialogue, nothing is known for certain concerning Diotima. For centuries, scholars tended to assume she was a real historical figure, as most other characters in the Symposium are. Modern critics, however, have often assumed—or at least suspected—that Diotima is fictitious.
Alcibiades is a wily and sharp-witted Athenian politician who, at the time of the Symposium, is in his early thirties. He arrives to the Symposium drunk and without an invitation, then proceeds to give a somewhat fulsome speech in praise of Socrates. The events of the Symposium take place right before a sharp downturn in Alcibiades's career: in 415 BCE, he will lead the Athenians on the disastrous Sicilian Expedition, then defect to Sparta after Athens turns against him. Plato's portrait of Alcibiades shows both his brilliance and his recklessness, two qualities that will dictate the course of his later life.
Aristophanes is a famous comic playwright of Athens. Apart from his appearance in the Symposium, he is known for satirical plays including Clouds (423 BCE) and Frogs (405 BCE). His speech, uncharacteristically serious in tone, gives a mythological account of the origin of love.
Agathon is a highly regarded Athenian tragedian whose work won the Lenaea (Athenian festival with a dramatic competition) in 416 BCE, an achievement that helps to date the events described in the Symposium. Today only a few lines of his plays survive. Within the Symposium, Agathon is described as the host of the party and the lover of Pausanias. His speech focuses on the divine attributes of Eros (i.e., Love).
Apollodorus, narrator of the Symposium, is a disciple of Socrates and a native of Phalerum. While on the road to Athens, he retells the speeches from the Symposium as a way to pass the time and entertain his fellow travelers. Once he has introduced the characters in the dialogue, Apollodorus fades quickly into the background.
Aristodemus of Cydathenaeum serves as Apollodorus's source about the goings-on at the Symposium. He is first described as a "little fellow" who "never wears shoes"—a comical description that suggests his desire to imitate Socrates. Notably, Aristodemus's own speech—if indeed he gave one—is not among those recorded in the Symposium.
Eryximachus is an Athenian physician and, according to other Platonic works, a long-standing friend of Phaedrus. Little is known of his life apart from what may be found in Plato's dialogues. In his speech, he argues that true love motivates one to lead a life of wisdom and moderation.
Pausanias is Agathon's lover, but information on his life is otherwise scarce. He makes a brief, unflattering appearance in Greek philosopher Xenophon's work entitled Symposium and is mentioned by a few other ancient authors. In Plato's dialogue, Pausanias distinguishes between a superior, "celestial" love and an inferior, "common" variety of love. The difference, he says, comes down largely to the intentions of the participants.
According to Eryximachus, Phaedrus is the one who has suggested the theme of love for the speeches at the Symposium. In his speech, the first of the evening, Phaedrus praises love as a deity who inspires selfless courage.