The longest-reigning pope in history is traditionally recognized as Saint Peter, the first pope, with an estimated reign of about 34 to 37 years around 30–64 or 30–67 AD, though exact dates are uncertain and debated by historians

. Among verified historical records, Pope Pius IX holds the longest confirmed papacy, reigning for 31 years, 7 months, and 23 days from 1846 to 1878

. Thus, while Saint Peter is regarded symbolically as the longest-serving pope, Pope Pius IX has the longest verified reign in documented history.