In Greek mythology, Elpis was the personification of hope, perhaps a child of Nyx and mother of Pheme. She was depicted as a young woman.
When Pandora opened Pandora's Box, she let out all the evils except one: hope. Apparently, the Greeks considered hope to be as dangerous as all the world's evils. But without hope to accompany all their troubles, humanity was filled with despair. It was a great relief when Pandora revisited her box and let out hope as well.
Her Roman equivalent was Spes the goddess of hope, traditonally defined as "the last goddess" (ultima dea), meaning that hope is the last resource available to men.