After the Council of Constance, the Catholic world gave the lake its current name, after the city Constantia (Konstanz), that, in turn, was named after a Roman emperor (either Constantius Chlorus or his grandson Constantius II).
After the Council of Constance, the latin speaking Catholic world gave the lake its current international name. It was derived from the city name Constantia (latin name of Konstanz), that, in turn, was named after a Roman emperor (either Constantius Chlorus or his grandson Constantius II).