Pulitzer Prize winner, Harvard-trained psychiatrist and best-selling author Charles Krauthammer, who came to be known as the dean of conservative commentators, has died. He was 68. The news of his demise was confirmed by friend and fellow commentator Bret Baier. Krauthammer was a longtime Fox News contributor. His death on Thursday has been expected after he wrote a heartbreaking letter to colleagues, friends and viewers on June 8. The letter said: "I have been uncharacteristically silent these past ten months. I had thought that silence would soon be coming to an end, but I'm afraid I must tell you now that fate has decided on a different course for me". Krauthammer had cancer, Fox News reported. It had relapsed. "It is aggressive and spreading rapidly. My doctors tell me their best estimate is that I have only a few weeks left to live. This is the final verdict. My fight is over," the letter added. In recent years, Krauthammer was best known for his nightly appearance as a panelist on Fox News' "Special Report with Bret Baier" and as a commentator on various Fox news shows. Krauthammer achieved mastery in disparate fields as psychiatry, speech-writing, print journalism and print journalism and television. He won the Edwin Dunlop Prize for excellence in psychiatric research and clinical medicine. Journalism honors included the Pulitzer Prize for Commentary for his Washington Post columns in 1987 and the National Magazine Award for his work at The New Republic in 1984. His book, "Things That Matter: Three Decades of Passions, Pastimes and Politics," instantly became a New York Times bestseller, remaining in the number one slot for 10 weeks, and on the coveted list for nearly 40. He is survived by his wife, Robyn and son, Daniel.