The origin of many literary modes and genres is lost in the mists of time (that of epic, for example), or is associated with the names of originators whose actual works have disappeared (like those of Thespis, the creator of Greek tragedy) or survive only in fragmentary form. The origin of pastoral, however, is well documented. For all extents and purposes, pastoral was invented by the Greek poet Theocritus around 275 BCE, and his chief pastoral poems have survived more or less intact for over 2200 years.
The pastoral mode incorporates an ironic perspective, in that what is represented (ostensibly the life and love of herdsmen or of those who have taken refuge among them) means much more than what appears on the pleasant …
Walker, Steven. "Pastoral". The Literary Encyclopedia. First published 06 April 2008
[https://www.litencyc.com/php/stopics.php?rec=true&UID=1224, accessed 21 August 2019.]