Diotima of Mantinea was a priestess and philosopher reputed to have been a teacher of Socrates. Though it is not the only reference to her the ancient philosopher made, he invokes her as the concluding authority on love in Plato's Symposium. He credits Diotima with the instilling of his own understanding of love during an all-night, all-male party where the high-born young men offer varied views on every aspect of love.
Diotima's take on the subject is the source of the concept of "Platonic love", a far more complex idea than simply nonsexual love. Addressing both love of men for women and love of men for other men, Diotima taught that love for the beauty of a young man or woman is the seed of the lifelong search for understanding of love, beauty and spiritual oneness. Eros, or the love for the physical form of the beloved, leads one to insights about beauty that culminate in recognition that there is beauty in all things. When one understands that all things being beautiful means all things can be loved, one reaches supreme enlightenment.
But did she exist? Some scholars regard Diotima as a fictional character created by Plato, possibly based on the intellectually respected mistress and later wife of of Pericles, Aspasia of Miletus. Others point to the fact that most of the characters in Symposium can be linked to historical Athenians. Whether or not Diotima was a real person, she can be said to have been one of the most influential philosophers of her day. What Plato says through her, no matter the origin, continues to figure in philosophical discussion and thought today and can be traced through the thinking and writing of great philosophers of both genders throughout.
Diotima's explanation of love: http://hompi.sogang.ac.kr/anthony/Classics/Diotima.htm