The period of forty-some years that Charles the Great / Charlemagne reigned as King of the Franks is considered by some as a golden age of the Frankish Kingdom. During that time the Frankish Kingdom was expanded, by conquest and acquisition, to include the Kingdom of the Saxons, Bohemia, Bavaria and Carinthia, and the Lombardy region of northern Italy. Charlemagne was an ardent supporter of the Church. He also was an advocate of education; he imported scholars from many countries to teach in the schools he established. His policies were, for the most part, fair and just, and as a result, his influence was moreso respected rather than feared.
When Charlemagne died in the year 814 A.D., the Kingdom of the Franks was once more divided into three parts among his sons. The partitions devised at that time would be confirmed by the Treaty of Verdun in 843, and would essentially remain unchanged to the present time. The western part corresponded to the region encompassed by modern-day France. The eastern part corresponded to the region that is encompassed by modern-day Germany. The region in the middle corresponded to the region encompassed by the modern-day countries of Belgium, Netherlands, Luxembourg, Switzerland and northern Italy.
From 814 onward through the Eleventh Century, the Western Roman Empire evolved out of the region that was inherited by Charlemagne's sons, Lothar and Louis. This "empire" is sometimes referred to as the Holy Roman Empire or the Roman Empire of the German Nation. As the names would imply, the ties between the Germanic realms and the Roman/Papal government had become greater than those between the Germans and the Franks in Aquitaine.
Out of the partition of the Kingdom of the Franks, following Charlemagne's death, rose the kingdoms of France and Germany. Both kingdoms underwent cultural and social changes as the concept of the feudal system became widespread. The sovereignty of Aquitaine, which was becoming known as France, had passed out of the hands of the Carolingian dynasty and into the hands of the descendants of Hugh Capet. The Capetian Dynasty of France would last into the Thirteenth Century. In the meantime, in the eastern Germanic kingdoms, the power was claimed by the descendants of the Saxon king, Henry I. Henry united the territories of the Franks, Saxons, Swabians and Bavarians in 919 and gave it the name of Regnum Teutonicorum, or the Kingdom of the Germans.
King Henry I's son, Otto established the Ottonian Dynasty of Germany when he succeeded to the throne in 936. Otto and his descendants consolidated their power throughout the various kingdoms of Germany in much the same way that Charlemagne had throughout the entire Frankish Kingdom. They also exercised their authority over Lombardy in northern Italy following Otto's marriage to the Lombard Queen Adelheid. Otto established a national church, the Reichskirche, and appointed bishops and abbots to positions that he titled "Princes of the Kingdom". Otto, with the approval of the Pope in 962, assumed the title of "Holy Roman Emperor".
Despite its auspicious beginnings, the Holy Roman Empire tended to be characterized by a constant struggle for power between the Emperor and the Pope. Added to the ecclesiastical vs imperial turmoil was the emergence of the feudal system, out of which emerged a new class in European society: the nobility. The nobility, spurred into existence by the creation of knightly religious orders who participated in the Crusades, challenged the authority of the Emperor.
The Holy Roman Empire can be outlined in maps of the Europe of the Eleventh Century, but it existed more in the title than in anything else. The various city states, feudal "duchies", baronies, counties and free cities, of which there were over three hundred, were collectively called the Germanies. The descendants of Otto developed a system of government which would bring about a reformation throughout the Germanies. In 1356 the Golden Bull was instituted by Charles IV of Luxembourg. A congress, called the Imperial Diet, which consisted of seven "electors" (i.e. the archbishops/princes of the most prominent realms: Mainz, Cologne, Trier, Bohemia, Saxony, Brandenburg and the Rhine), lesser princes/bishops and representatives of the free cities was established by Maximilian I in 1493. The Imperial Diet was essentially a diplomatic congress to make laws; the emperor was the instrument to execute the laws made by the Imperial Diet. As such, it was intended to function as a guarantee of democratic government for the Germanies.
Within the Holy Roman Empire a number of unions were established between city-states and feudal kingdoms. The most enduring of these unions was the "Perpetual Pact" between the cantons of Uri, Schwyz and Unterwalden of 1291. Formed to provide mutual defense against the Hapsburg family, which had attempted to lay claim to the region. The cantons of Berne, Glarus, Lucerns, Zug and Zurich soon joined the Pact, and the Swiss Confederation came into being.
The Holy Roman Empire endured into the first years of the Ninteenth Century. But by the year 1500, it had become reduced in both size and power. Certain territories or realms had achieved their independence from the Holy Roman Empire. The Papal States had gained their independence from Lombardy. The Venetian Republic also claimed a portion of Italy that had been settled by the Germanic tribe of the Lombards. The Habsburg family had amassed a considerable collection of estates in the Austrian Kingdom beginning in the late-1200s, and continued to build their own "empire" through the next few centuries. By the year 1500 they held Austria, the Tryol region of Bavaria, Luxembourg, the Netherlands and lands in northern France. Increasing invasions from the east, including those of the Mongols led by Genghis Khan, tore away at the easternmost regions that had been earlier conquered by the Germanic tribes. The Holy Roman Empire, at the beginning of the Sixteenth Century still retained the majority of the regions drained by the Rhine, Elbe and Danube Rivers, the Swiss Confederation, Saxony and the Po Valley of northern Italy.
According the James E. Gillespie, in his book, A History Of Europe 1500-1815, the Holy Roman Empire can be said to have lasted until the year 1806 when it was finally brought to an end by the invasions of Napoleon into Germany and Austria. The Holy Roman Empire was dissolved, and the Confederation of the Rhine was created in its stead. But the Empire had already started to collapse during the period of the Reformation (beginning in 1517). As the Roman Catholic Church's unity was destroyed by Martin Luther's protests, so the Holy Roman Empire found itself breaking up into a plurality of separate states. The relative stability that had existed in the Germanic lands for so many centuries, which had kept the Holy Roman Empire thriving, came to an end in 1608 with the formation of the Protestant Union and the Catholic League. The stage was set for a major war.