Epipsychidion, poem in couplets by Percy Bysshe Shelley, written in 1821 in Pisa (Italy). It is dedicated to Teresa (“Emilia”) Viviani, the teenage daughter of the governor of Pisa, who had been confined in a nunnery by her father. Shelley renamed her Emily and imagined her living in an ideal ménage à trois with him and his wife; eventually, he and Emily would live perfect lives on an island paradise. In his attempts to convey the rapture of his feelings, Shelley lapsed into self-parody and later found the poem something of an embarrassment.