High-water marks in Roman history - literally.

Latin Inscription

Anno Domini MCCCCXXII In Die Sancti Andree Crevit Aqua Tiberis Usque Ad Sumitatem Istius Lapidis Tempore Domini Martini Pape V Anno VI ("In the year of the Lord 1422 on the day of Saint Andrew [Nov. 30] the water of the Tiber rose as far as to the top of this stone, in the time of the Pope Martin V, his sixth year.")

The oldest of numerous such flood markers on the exterior wall of Santa Maria sopra Minerva.

Paul Pascal
Paul Pascal is Professor Emeritus of Classics at the University of Washington. In 1953 he began teaching at the University of Washington, where he specialized in Medieval Latin studies. He is a Fellow of the American Academy in Rome.