There are many links with butterflies in mythology from all over the world, many of which, in particular Greek mythology, link butterflies to the human soul. The Ancient Greeks also considered butterflies as the souls of those who had passed away.
In ancient Greek the word for butterfly is "Psyche", which translated means "soul". This was also the name for Eros' human lover and when the two figures are depicted they are often surrounded by butterflies.
Eros (called Cupid in Roman Mythology), was the son of Aphrodite and Hermes. He took a human woman named Psyche as his wife on the condition that she would never see his face and he would only visit her at night. Their nightly meetings were full of love and passion, but Psyche started to fear that her husband might be an ugly monster.
Urged by her sisters, she hid a knife and candle by the bedside one evening before Eros came. After he had fallen asleep, Psyche silently lit the candle and gazed on the face of her husband. She saw not an ugly beast as she had expected, but a most handsome young man with wings. In her surprise she spilt some wax from the candle on his sleeping face, waking Eros from his sleep. As he flew away he cried "Oh foolish Psyche! Is it thus you repay my love? But go; return to your sisters whose advice you seem to think preferable to mine! I inflict no punishment on you, other than to leave you for ever."