Arcades was part of a series of small-scale aristocratic entertainments, probably performed during the summer of 1633 (Carey and Fowler cite Milton's reference to thick foliage at 88-9 to support this dating). The piece honors Alice Spencer, the Dowager Countess of Derby. Her first husband was Ferdinando Stanley, Lord Strange (died 1594), thus she was also known as Lady Strange. Her kinsman, Edmund Spenser dedicated his Tears of the Muses (1591) to her, and she was the "sweet Amaryllis" in his Colin Clout's Come Home Again (1595). John Davies of Hereford dedicated Holy Rood to her, and she played the part of Zenobia in Ben Jonson's Masque of Queens. She married her second husband, Sir Thomas Egerton, in 1600, and her second daughter married Sir Thomas's son, Sir John, who became the Earl of Bridgewater in 1617. A Mask was written for him. Milton's connection with the Egertons was likely through his friend Henry Lawes, who taught Music to the Earl's children beginning in 1626.
The name and the genre of the work are pastoral. The title — meaning "the Arcadians" — is intended to recall images of classical Arcady, a region of Greece imagined as full of shepherds, nymphs, and pastoral poetry. Milton was well versed in the tradition of representing Arcadia as a pastoral ideal, and was probably familiar with the pastoral poetry of Spenser, Shakespeare, Jonson, Drayton, William Browne, and George Wither, and certainly Sir Philip Sidney's prose pastoral epic, Arcadia. Milton's masque-like pageant honors the Countess by placing her at the center of the movement of a group of noble persons. The short body of the poem is thematically very rich. Milton praises the virtues of motherhood, wisdom, and celestial beauty through the use of numerous classical allusions (especially lines 20-22). He also introduces, and alters, Platonic cosmology and the Pythagorean doctrine of the Music of the Spheres. The Genius of the wood may introduce some pagan elements, and some critics (John M. Wallace, for example) interpret Arcades as a progression from the profane to the religious, from the classical Renaissance of Italy to the transalpine reformed ethos of the north. Since Arcades was meant to flatter the Countess, it seems more likely, as Flannagan suggests, that the Genius embodies the magic and moral power of the artist in free service to aristocrats like the Countess and her descendants.
The copy-text is from Poems (1645) with some reference to the Trinity Manuscript, which, as Shawcross maintains, was probably a transcript made after the first performance.