Marvell's poetry further challenges conventionally defined relations between literature and history because it is difficult to date a good deal of it with any precision. The Marvell who emerges from the criticism of the last two decades is of a socially engaged figure working out a sophisticated and influential political philosophy. Goldberg, in claiming that Marvell's poem is 'only, and entirely, self-referential, "about" itself, also claims it is about 'what it represents in the world'. One of the principal features of this transformation has been the rediscovery of Marvell, with Milton, as promoters of a godly English Republic during the Civil War period of 1640-60. Francis Barker's discussion of Marvell's most widely-known lyric, 'To his Coy Mistress', considers the question of the body's possession by a male author. Marcus's view of Marvell is much influenced by Bakhtin's theory of the carnivalesque, the 'upending' or inversion of serious culture through its parody.