In undertaking it at this period he was missing a great opportunity.

He might have been the apostle of toleration in England, as Roger Williams had been in America.
The moment was most favourable.

Presbyterianism had got itself established, but could not pretend to represent the majority of the nation.

It had been branded by Milton himself in the memorable line: "New Presbyter is but old Priest writ large." The Independents were for toleration, the Episcopalians had been for the time humbled by adversity, the best minds in the nation, including Cromwell, were Seekers or Latitude men, or sceptics.

Here was invitation enough for a work as much greater than the "Areopagitica" as the principle of freedom of thought is greater than the most august particular application of it.
Milton might have added the better half of Locke's fame to his own, and compelled the French philosophers to sit at the feet of a Bible-loving Englishman.