Plutarch was not a profound philosopher but a popularizer in the best and most enduring sense of the word. He did not establish a philosophic system but was eclectic in his use of various systems. He warmly admired Plato and knew Pythagoras and other Greek philosophers. He severely criticized Epicureanism and stoicism but used these systems as it suited him. One critic finds him a humanist par excellence; others see him inclined toward mysticism and monotheism. He was an author of uncommon common sense who influenced Sir Philip Sidney, Edmund Spenser, Ben Jonson, William Shakespeare, John Dryden, John Milton, Robert Herrick, George Chapman, Jonathan Swift, Walter Savage Landor, William Wordsworth, Robert Browning, Mary Shelley, and H.G.