structural:summarization
Final days and death

After his resignation, Marshal Baron Mannerheim bought Kirkniemi Manor in Lohja, intending to spend his retirement there. In June 1946, he underwent an operation for a perforated peptic ulcer, and in October of that year he was diagnosed with a duodenal ulcer. In early 1947, it was recommended that he should travel to the Valmont Sanatorium in Montreux, Switzerland, to recuperate and write his memoirs. Valmont was to be Mannerheim's main residence for the remainder of his life, although he regularly returned to Finland, and also visited Sweden, France and Italy.

Because Mannerheim was old and sickly, he personally wrote only certain passages of his memoirs. Some other parts he dictated. The remaining parts were written from his recollections by Mannerheim's various assistants, such as Colonel Aladár Paasonen; General Erik Heinrichs; Generals Grandell, Olenius and Martola; and Colonel Viljanen, a war historian. As long as Mannerheim was able to read, he proofread the typewritten drafts of his memoirs. He was almost totally silent about his private life, and focused instead on Finland's history, especially between 1917 and 1944. When Mannerheim suffered a fatal bowel obstruction in January 1951, his memoirs were not yet in their finished form. They were published after his death.

Mannerheim died on 27 January 1951 (28 January Finnish time), in the Cantonal Hospital in Lausanne (French: L'Hôpital cantonal à Lausanne; modern Lausanne University Hospital), Switzerland. He was buried on 4 February 1951 in the Hietaniemi Cemetery in Helsinki in a state funeral with full military honours.