Leo XIII holds the record as the oldest reigning Pope, reaching the age of 93. His papacy spanned 25 years, from 1878 to 1903.
However, the longest documented tenure belongs to his predecessor, Pius IX (1846–1878), who led the Church for over 31 years before passing away at 85 years and nine months.
It is believed that only Saint Peter, the first Bishop of Rome, served longer—approximately 34 years.
