Psellos wrote a long letter to Keroularios listing differences between them. Keroularios was an angel of heaven, Psellos had his feet on the ground; Keroularios was immutable, Psellos changeable; Psellos was always reading, Keroularios was not; Keroularios was a proud aristocrat, Psellos was not, and so despised Psellos, despite his high fame all over the world; Keroularios had a dominant public role, Psellos was a nervous pedant. He advised Keroularios that he needed militancy but not violence, he should be retiring, not try to rule; Psellos had written Keroularios' biography, spreading his fame widely