Misdated Popes: a Mistake in the Chronology of Seventh-Century Bishops of Rome

Abstract

The letter sent by Kyros of Alexandria to Sergios of Constantinople in 638 appears to contain a chronological contradiction: it implies that Sergios was aware before his death of the election of Severinus as the new bishop of Rome two months earlier. Given the travelling times in the seventh century, this is impossible. The problem originates in a mistake made by Louis Duchesne when calculating the chronology of the popes for his edition of the Liber pontificalis: for the period 619–49, all his dates are one year too late. This change of the chronological framework affects the interpretation of a number of documents.