How were the borders of the Holy Roman Empire established?

Question

We all know that the Holy Roman Empire was a collection of minor Germanic states in the Medieval and Renaissance Europe. Wikipedia stated that:

The Holy Roman Empire was a multi-ethnic complex of territories in central Europe during the medieval and early modern periods until its dissolution in 1806.

A question which I have been bothered, and I am sure most of you do, is how exactly were their borders defined? In two maps below the borders seems to sometimes cross another border. Furthermore, the borders seem to be changing with time.

This first map is one of Europe in the 16th century. The Holy Roman Empire is outlined in purple.

This second map is one of Europe in 1700:

References:

• First Map : http://www.euratlas.net/history/europe/1500/1500.jpg
• Second Map : http://upload.wikimedia.org/wikipedia/commons/3/3b/Europe,1700-_1714.png

Answer 1

The Holy Roman Empire, as an "empire", did not have a territory of its own. It must be understood in the context of feudalism: a number of princes/kings/bishops/whatever were tied, through sworn allegiance, to the elected Emperor. In a way, we can say that the Empire extended exactly as far as these constituent elements extended. On the other hand, the Emperor did not "own" these lands. In the vassal-suzerain relationship, the vassal owes support and a solid does of obedience, but is still the rightful owner of his lands (and in the feudal world, land ownership is merged with the judicial power).

The Emperor could own some territories, not because he was Emperor, but through personal inheritance. The imperial crown did not come with a specific dedicated domain. This matters a lot from a strategic point of view: in Medieval times, the size of the army you could muster depended on your resources, i.e. the lands that you owned. The Emperor could, as the ultimate suzerain for all Empire territories, requests his vassals to provide for troops (that's what Frederick I did for the ill-fated Third Crusade), but in order to maintain order within the Empire (i.e. to keep his own vassals under his control), the Emperor had to rely on his own resources.

So, in practice, the Holy Roman Empire had not so much a territory than an influence zone (thus with a "border" that is necessarily fuzzy), and the Emperor's regime was chronically weak. Some principalities that were formally part of the Empire were paying heed to what the Emperor had to say only on a very occasional basis. To a large extent, the Empire was operating in ways very similar to the contemporary Caliphate, with the Caliph being recognized as the formal commander of all Muslims, but with an actual power heavily dependent on his personal force of will and political guile.

Answer 2

You have confused the very real changes that occurred to the borders over the 170 years from roughly 1520 to 1700 with the concept that the borders were vague throughout that time. That span of years encompasses both the Thirty Years War in Germany, the Eighty years War of Dutch Independence, the War of the League of Augsburg, and several smaller conflicts.

As a consequence of the Battle of Pavia in 1525, suzerainty over Northern Italy(which had long been under French influence though technically part of the HRE) was transferred from Hapsburg Austria to Hapsburg Spain, transferring it out of the HRE.

The Peace of Westphalia included a ratification of independence of both Netherlands and Switzerland.

The Treaty of Ryswick included a ratification of the loss of Franche-Comte and Alsace (including Strasbourg) by the Holy Roman Empire to France.

Other than in Italy, the Rhinelands, and Low Countries as outlined above, the border of the HRE between the two maps (and time periods) is unchanged from Bremen east to Danzig, south to Trieste, and west again to the Swiss-Tyrol border.

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Update

An excellent overview of the HRE's legal structure includes documentation of its boundaries over time:

The external boundaries of the Empire varied over time. In particular, the western boundary shifted many times eastward, as French kings encroached on the Empire as they enlarged their domains. Thus Provence (1246), Dauphiné (1349), the bishoprics of Metz, Toul, Verdun (1558), Alsace (1648), Franche-Comté (1678), Lorraine (1736), the west bank of the Rhine (1801) were incorporated into France, losses that were eventually acknowledged by the Emperors. There were losses elsewhere: the Swiss cantons, practically independent of their Habsburg overlords since the Middle Ages, were formally set free at the Peace of Westphalia in 1648.

and its composition as a collection of sovereign states

A State of the Empire (Reichsstand, status Imperii) was a member having a seat and a vote at the Reichstag (Sitz und Stimme). The corresponding adjective is reichsständisch.

Here is a comprehensive list of the states composing the HRE in 1521, 1755, and 1792.

Answer 3

In another thread: How were the territories added to (and thus the limits set in) the Holy Roman Empire I have a post discussing not where were the borders of the Holy Roman Empire, but IF there were borders of the Holy Roman Empire.

Historians of Southeast Asia have the concept of a "mandala" realm, where the authority of the sovereign gets less and less the farther away from the center, so it is very had to find the outermost limits of the realm. Many other realms in history have been similar to this with different zones of different degrees of connection and subordination to the central power.

Historical maps of the Holy Roman Empire seem to deal with its different zones with different degrees of being inside or out of the empire very badly. Makers of historical maps want to show precise borders.

The first map shown above for the 16th Century has an error in showing too much of south eastern France on the French side of the imperial border. The kings of France acquired and ruled lordships, counties, margravites, etc. in the kingdom of Burgundy/Arles, which was part of the empire, and ruled them as the lords, counts etc. of those fiefs. The kings of France acknowledged that those fiefs ere part of the Holy Roman Empire, though of course they were even more disloyal to the emperor than the other lords in the empire.

The second map repeats that error. Note that the second map shows the Habsburg territories such has Hungary, Bohemia, and Austria, all the same color, with the border of the Holy Roman Empire running thorough it to separate the territories within the empire from those outside the empire. It does the same with territories of the Kings of Prussia, Sweden, and Denmark-Norway inside and outside of the Empire's borders. The map maker could have done the same thing for the border with France, showing that the French king was also the ruler of territories that were still within the Empire.

The second map also fails to show that the states in Northern Italy outside of Venice and the Papal States were still part of the Kingdom of Lombardy and the Holy Roman Empire. The mapmaker may have assumed that it was impossible for a realm to have two parts that were separated by territories of other realms. That would have been just as crazy as - for example - East and West Pakistan being separated from each other by the Republic of India in 1947-1971, or East Prussia being separated by part of Poland from the rest of Germany in 1919-1939, or East Prussia being separated by Lithuania and Belarus from the rest of Russia from 1991 until now.

In 1708 a number of lords in northern Italy, such as Ferdinand Charles, Duke of Mantua and Montferrat, discovered that their lands ere still part of the the Holy Roman Empire when the Emperor Joseph I had their fiefs confiscated for aiding the French army.

These few examples show that maps often show the borders of the Holy Roman Empire inaccurately.