Morgan Llwyd was the author of seven prose works in Welsh and English, a considerable body of poetry, and translations of passages from the work of
Jakob Böhme, taken from the English translations of
John Sparrow. His most significant prose work is
Llyfr y Tri Aderyn ('The Book of the Three Birds'), comprising a religious and political debate between a Raven, representing the
High Church Anglican and
Royalist faction under Cromwell's
Commonwealth; an Eagle, representing its government; and a Dove, representing the
Puritan faction, who convinces the Eagle of the truth of Puritan teaching and the validity of
theocracy. In addition to this, the Raven and the Dove are compared with the Raven and Dove sent out from
Noah's Ark to search for dry land, and history is represented as a hiatus between the divine judgement given in the
Genesis flood narrative and the
Last Judgement, which Morgan Llwyd expects to come very shortly. Morgan Llwyd's three shorter prose works in Welsh are ''Llythyr i'r Cymry Cariadus
, Gwaedd yng Nghymru yn Wyneb pob Cynwybod
and Cyfarwydd i'r Cymru
, in which he stresses the urgent need of his readers for a personal reconciliation with God. Of his three tracts in English, Lazarus and His Sisters Discoursing of Paradise
and Where Is Christ?
deal with theological matters, while An Honest Discourse Between Three Neighbours'' explores differing attitudes towards Oliver Cromwell's rule. ==Critical response==