How old was the youngest man acknowledged by the Vatican as Pope?
The young Pope John XII was approximately 18 years old when elected Pope. This youngest Pope in history faced charges of sacrilege, simony, murder, adultery, perjury and incest shortly after his installation as Rome’s spiritual and temporal authority. Although he apparently did not deny the charges, he did excommunicate those bishops who tried to impeach him. After mounting a successful retake of Rome, the then-25-year-old Pope died under mysterious circumstances. Source: Reference.com