The Legacy of Rome: A New Appraisal (1992), edited by Richard Jenkyns, so far has proved to be a treasure trove of fascinating information. The book focuses on how the Latin classics--and Roman culture in general--influenced medieval and, more significantly, Renaissance literature and historiography. I picked the book up at my favorite second-hand store.
Jenkyns, of Oxford University, contributed two essays to the collection, the second of which, entitled "Pastoral," I found to be particularly enjoyable.
"One oddity about pastoral is that it is an exclusively European (or western) form. This is not true of most literary genres. We may happily speak of a Chinese novel, and there is surely no great problem in talking about a Chinese epic or a Chinese satire. But it would make no sense to describe a classical Chinese poem or story as pastoral (unless, by metaphor, it were being compared to European work)."
Pastoral, in short, contains classical Greek motifs (or at least allusions to ancient Greece) and significant characters lounging around in the shade of trees, tending their sheep, moaning over unrequited love, etc.
It is generally accepted that Virgil's Eclogues have become the model of pastoral poetry, but Jenkyns notes that the genre was truly devised in the late 16th Century, by romantic (with a small "R") writers intent on evoking mellow Arcadia. (It was these romantic pastoral stories to which Cervantes attributed Don Quixote's delusions or heroism.)
Jenkyns' essay is worth reading twice, and I think I will.