The Countess of Pembroke's Arcadia, also known simply as the Arcadia, is a long prose pastoral romance by Sir Philip Sidney written towards the end of the 16th century. Having finished one version of his text, Sidney later significantly expanded and revised his work. Scholars today often refer to these two major versions as the Old Arcadia and the New Arcadia. The Arcadia is Sidney's most ambitious literary work by far, and as significant in its own way as his sonnets. Source: Wikipedia (en)