Lord Byron's Cain and Thomas Moore's The Loves of the Angels are linked by critical accusations of blasphemy which threatened their legal and commercial integrity. Comparing the critical and legal reception of the two works and the subsequent responses of the two authors reveals complex formal and informal systems of regulation that were activated in the case of blasphemous publications. Legal findings against Cain provoked Byron to insist on his authorial autonomy but also to acknowledge the growing power and influence of a mass reading public. Moore's substitution of Islam for Christianity at his poem's religious foundation represented a flexible mode of authorship where its broad social and cultural influences were reflected in his recognition of textual contingency. Together, the two cases highlight paradoxes in the legal control of intellectual property and blasphemy in the Romantic period, while the two authors responses provide a means of examining their differing perspectives on authorship and revision. ; Portions of this work were supported by an Irish Research Council / Marie Skłodowska-Curie COFUND CARA Fellowship. ; peer-reviewed ; 2018-06-01