Napoleon visited Erfurt a number of times during the French occupation . He took a particular interest in Petersberg Citadel . He stayed in Erfurt from 27 September to 14 October 1808 , when he meet with Tsar Alexander I of Russia for the Congress of Erfurt . The two leaders visited Petersberg Citadel together during the Congress
Congress of Erfurt
Congress of Erfurt
Petersberg Citadel