John Milton was an English poet, classicist, and fearless advocate for civil liberty, who served the Commonwealth of England under Oliver Cromwell. He is best known for his epic poem "Paradise Lost" , a work of sublime imagery and hidden heresy. In this long essay, Macaulay combines literary criticism with political history, writing that to Milton, almost alone among his contemporaries, belonged "the glory of the battle which he fought for, the species of freedom which is the most valuable, and which was then the least understood, the freedom of the human mind."