Then for nearly twenty years the poet of great achievement and still greater promise disappears. We hear no more songs, but only the prose denunciations and arguments which are as remarkable as his poetry. In all our literature there is nothing more worthy of the Puritan spirit than this laying aside of personal ambitions in order to join in the struggle for human liberty. In his best known sonnet, "On His Blindness," which reflects his grief, not at darkness, but at his abandoned dreams, we catch the sublime spirit of this renunciation. Milton's opportunity to serve came in the crisis of 1649. The king had been sent to the scaffold, paying the penalty of his own treachery, and England sat shivering at its own deed, like a child or a Russian peasant who in sudden passion resists unbearable brutality and then is afraid of the consequences. Two weeks of anxiety, of terror and silence followed; then appeared Milton's _Tenure of Kings and Magistrates_. To England it was like the coming of a strong man, not only to protect the child, but to justify his blow for liberty. Kings no less than people are subject to the eternal principle of law; the divine right of a people to defend and protect themselves,--that was the mighty argument which calmed a people's dread and proclaimed that a new man and a new principle had arisen in England. Milton was called to be Secretary for Foreign Tongues in the new government; and for the next few years, until the end of the Commonwealth, there were two leaders in England, Cromwell the man of action, Milton the man of thought. It is doubtful to which of the two humanity owes most for its emancipation from the tyranny of kings and prelates.