Final answer:
John Milton supported the puritan reformers and the republican government led by Oliver Cromwell during the English Interregnum that followed the execution of Charles I.
Step-by-step explanation:
The poet John Milton was an ardent supporter of the Parliamentary forces during the English Civil War and the subsequent government which arose after the execution of Charles I. During the tumultuous years when England grappled with conflicts between the monarchy and Parliament, Milton backed the puritan reformers and the Commonwealth government, headed by Oliver Cromwell as Lord Protector. This period, post-1649, known as the Interregnum, saw England transition into a republic, albeit one that has been described by many historians as a military dictatorship due to Cromwell's extensive powers. Cromwell was a devout Puritan himself and supported certain levels of religious toleration, except for Catholics, as outlined in the Instrument of Government. As such, Milton, known for his works such as Paradise Lost, was in favor of a Cromwellian republican government during the English interregnum.