He came up with the influential idea of platonic love.

Plato provides insight into the idea of beauty and love in his book, Symposium. Seven characters in this work of philosophical fiction deliver lectures extolling the virtues of Eros, the deity of desire and love. According to legend, here is where the first seeds of what we now understand as Platonic love were planted. This is a passionate, otherworldly bond that does not involve sexual activity.

Through these characters, Plato examines a range of perspectives. Socrates, the main character, talks about how men should first fall in love with a particularly attractive person, then move on to loving a particular example of beauty in general, and finally loving moral rather than physical beauty. A person should be admired for their expertise, as well as for who they are as an individual. The following phase should be to love intelligence, and then one should be able to love and appreciate heavenly beauty.