 In later years, Nietzsche moved frequently in the effort to find a climate that would improve his health, settling into a pattern of spending winters near the Mediterranean (usually in Italy) and summers in Sils Maria, Switzerland. His symptoms included intense headaches, nausea, and trouble with his eyesight. Recent work (Huenemann 2013) has convincingly argued that he probably suffered from a retro-orbital meningioma, a slow-growing tumor on the brain surface behind his right eye. In January 1889, Nietzsche collapsed in the street in Turin, and when he regained consciousness he wrote a series of increasingly deranged letters. His close Basel friend Franz Overbeck was gravely concerned and travelled to Turin, where he found Nietzsche suffering from dementia. After unsuccessful treatment in Basel and Jena, he was released into the care of his mother, and later his sister, eventually lapsing entirely into silence. He lived on until 1900, when he died of a stroke complicated by pneumonia.