The Holy Roman Empire, also known as the Holy Roman Empire of the German Nation after 1512, was a polity comprising and controlling much of Central and Western Europe, headed by the Holy Roman Emperor and characterized by a decentralized political structure. It developed in the Early Middle Ages, and lasted for a millennium until its dissolution in 1806 during the Napoleonic Wars. Initially, it consisted of three parts—Germany, Italy, and Burgundy—held together by the emperor's overlordship. By the 15th century, imperial governance had become concentrated in and upon the Kingdom of Germany, as the empire's effective control over Italy and Burgundy had largely disappeared.