This chapter demonstrates how a recovery of the histories which inspire writing enables recognition of the powerful imaginative contexts which help generate history. Detailed historical contextualisation is an opportunity to show how An Horatian Ode reflects the larger visionary possibilities of its time - notably the emerging belief of the English Republic as a new 'Rome in the West', a power which would lead a Protestant assault on Roman Catholic Europe, an enterprise imbued with messianic, millenarian, potential. Oliver Cromwell was the leading personality of the regime that emerged after the execution of Charles I in 1649. To the surprise of his contemporaries, his preeminence received no formal recognition. Andrew Marvell has given timelessness to a desperate and portentous moment in his country's history, the arrival of Oliver Cromwell in England in the summer of 1650. The ode of 1650 tells about Marvell's Horatian transition.