Pope wrote this mock-epic poem at the request of his friend John Caryll to help heal a rift between two prominent Catholic families. In real life, Lord Petre had taken a lock of Arabella Fermor's hair without her permission, causing a quarrel that blew out of proportion.
The poem is a mock epic because it uses the epic form, a genre meant for serious subjects, such as the Trojan war in Homer's Iliad, and applies it to such a trivial issue as the loss of a lock of hair. The humor comes in the grandiose and overblown way this hair theft is described, complete with lamentations, exclamations, and the lock of hair ascending to the moon at the end of the poem. Pope populated his mock-epic world with sylphs and made as much of Belinda's petticoat as Homer did of Achilles's shield.
Pope wanted to use humor to heal an argument but also to show that the aristocrats and leaders of his day lacked the heroism of figures from classical literature. By poking gentle fun at them, he hoped to inspire them to worry about more important subjects than card-playing, hair, and flirtations.