Complex sentence: The prince retired from active duty after being diagnosed with tuberculosis in June 1940 and spent most of World War II convalescing at a villa in Gotemba, Shizuoka prefecture, on the eastern foot of Mount Fuji.
Split into simpler sentences: The prince retired from active duty after being diagnosed with tuberculosis in June 1940. He spent most of World War II convalescing at a villa in Gotemba, Shizuoka prefecture, on the eastern foot of Mount Fuji.