Samson Agonistes was published with Paradise Regained in 1670 or 1671. Its date of composition is uncertain, most probably some time during 1660-70. The topical references close to the surface of the poem have led some critics to place the tragedy to 1660-1 when the reparations of the Restoration were at their height. It is doubtful that Milton would have interrupted Paradise Lost to compose Samson. That is not to deny the origin of certain passages from this point in Milton's life in Samson Agonistes. Nevertheless there is good reason to concur with the traditional judgement and place Samson as Milton's last work - perhaps around 1670, when the poet's sense of 'heroic past and ignoble present' was re- invigorated.
Milton's oeuvre has been notoriously difficult for critics and students to interpret in comparison with other great figures of English literature. Milton presents particular difficulties: the poet created lengthy works based on religious convictions that have became largely antiquated in modern society. Without understanding of these it will be difficult to access the poet's meaning and intentions. The great nature of the topics Milton chose for literary endeavour invite comparisons with other weighty literary figures such as Dante and Shakespeare, even the metaphysical poets such as Donne.
The mental configuration from which Milton himself was writing and that of his intended audience was very particular to say the least. It is an intensely internalised view. The nature of Milton's themes and his underlying great purpose removes his poetry from ordinary concerns and experiences of mankind to the higher concerns of the universality of divine providence, the reality of evil, the hope of redemption, and the unity of the human race. These are Milton's intertwined central themes, not like Homer's desire to tell a good story, Dante's objective to provide a narrative exposition of a theological system, or Shakespearean analysis of character psychology. They provide the structural unity to Milton's work.
The public background, given that there are numerous allusions throughout his poetical works to the religio-political environment of the mid-seventeenth century, is indeed an aspect of Milton's tragedy. It is not the focus however. That, as indicated above, rests in Milton's theological or spiritual concerns. As outlined in the prefatory argument, Milton was interested in the literary dimensions of writing a tragedy true to the ancient Greek manner as much as, if not more than, autobiographical and political overtures he could invest in the work.
More recently critics have begun to view Milton's three major poetical works together, seeing them as a coherent tripartite didactic program, grounded in three parables. Each parable describes one or more divine interventions, and singles out an important component of the prophetic moment as its subject. Hence, Milton begins with Paradise Lost as the history of an alienation of worldly discourse from God that will require intervention, by means of the prophetic moment, if it is to be made a "fortunate fall." The poet continues with an examination of a crucial phase of that intervention, the moment of obedience, of Jesus' refusal of self-will, in Paradise Regained. Finally, in Samson Agonistes, he brings forward the idea that Jesus' moment of obedience cannot be regarded as a uniquely intercessory incident, but something which can be imitated in even desperately adverse circumstances. The key to Milton's project is his expectation that the reader, taught by his divinely inspired parables, will be able to repudiate the outward Paradise for which the Puritans so long and mistakenly sought, and begin to build the inward New Jerusalem to which the Spirit of God calls them. The poet's intention is to make prophets of his readers.
Thus the reader and student of Milton's Samson Agonistes has several strands of interpretation to follow - the political, the theological, the autobiographical, and the literary. The first three are undeniably intertwined, and it is perhaps false to separate them and consider them individually.