<P> Endymion is a poem by John Keats first published in 1818 . It begins with the line "A thing of beauty is a joy for ever". Endymion is written in rhyming couplets in iambic pentameter (also known as heroic couplets). Keats based the poem on the Greek myth of Endymion, the shepherd beloved of the moon goddess Selene . The poem elaborates on the original story and renames Selene "Cynthia" (an alternative name for Artemis). </P> <P> It starts by painting a rustic scene of trees, rivers, shepherds, and sheep . The shepherds gather around an altar and pray to Pan, god of shepherds and flocks . As the youths sing and dance, the elder men sit and talk about what life would be like in the shades of Elysium . However, Endymion, the "brain - sick shepherd - prince" of Mt . Latmos, is in a trancelike state, and not participating in their discourse . His sister, Peona, takes him away and brings him to her resting place where he sleeps . After he wakes, he tells Peona of his encounter with Cynthia, and how much he loved her . </P>

Who wrote the line a thing of beauty is a joy forever