Constance, Germany
Town in Baden, and former state of the Holy Roman Empire. Christianized about the 2nd century , and fortified by the Romans, 304 , Constance became an imperial city in 1192 , was the scene of the Sixteenth cumenical Council (1414 -1418 ) and, from the 7th century until the Reformation, was the seat of the largest diocese in Germany , including among its bishops , Saint Conrad (934 -975 ) and Saint Gebhard II (979 -995 ). From the 13th century , these prelates were princes of the German Empire, and had temporal jurisdiction over a principality of about 482 square miles, with a population of some 50,000, which principality was divided between Baden and Switzerland in 1802 . The diocese , which sustained great losses during the Reformation, was dissolved by Pope Pius VII in 1821 .