A map released by World in Maps visualises the tangled inheritance he acquired, with light-blue, dark-blue, orange, and red shading delineating his Spanish, Aragonese, Burgundian, and Austrian possessions.

The map highlights how the combined crowns of Castile and Aragon gave him the Iberian Peninsula and vast colonies in the Americas; the Burgundian lands brought him the Netherlands; and the Austrian realms added central European duchies. Red lines trace the borders of the Holy Roman Empire, over which he presided as emperor.

Modern historians describe Charles V as presiding over the largest collection of European land since Charlemagne . According to ThoughtCo , by the age of twenty, the young Habsburg was simultaneously “Duke of Burgundy, King of the Spanish Empire and Habsburg territories, which included Austria and Hungary, as well as Holy Roman Emperor”.

These titles did not come from a single inheritance; instead, they were accumulated gradually through the dynastic marriages of his grandparents and the untimely deaths of relatives. Each territory maintained its laws and institutions, leaving Charles to juggle competing interests and local privileges.

The Spanish inheritance alone was huge. When his maternal grandfather, Ferdinand II, died in 1516, Charles inherited the Spanish Empire, including the peninsular region of Spain, the kingdoms of Naples and Sicily, the Mediterranean islands of Sardinia, and large swaths of the Americas.

He declared himself king while his mother, Joanna, was still alive. This action triggered unrest among Castilian towns and nobles. Two years later, he was elected King of the Romans (he would be crowned Holy Roman Emperor in 1530), adding the nominal leadership of Germany to his growing titles.

The death of his paternal grandfather, Maximilian I, in 1519 gave him the Habsburg “hereditary lands” of Austria, Tyrol and Styria, while the earlier death of his father, Philip the Handsome, in 1506 made him heir to the wealthy Burgundian Netherlands.

A historical essay published by The World of the Habsburgs mentions that the emperor “ruled over vast possessions in Europe and America” and that his reign marked the division of the Habsburg dynasty into Spanish and Austrian lines.

Silver from the New World financed his campaigns against France, the Ottoman Empire and Protestant rebels, while revenues from the Low Countries fed an imperial bureaucracy that relied on cultures and languages.

Yet governing such a widespread empire proved difficult. Charles’s territories were said to be independent countries with little common interest; many had their systems of government and jealously guarded privileges.

In Spain, he faced uprisings from the Comuneros and later Catalan and Aragonese rebels; in Germany, he was drawn into religious wars against the Protestant princes. To secure his election as emperor, Charles took on large debts from the Fugger banking family and spent much of his reign travelling between courts to placate nobles.

By the 1550s, the strain of ruling the numerous territories had taken its toll. Charles abdicated in stages between 1554 and 1556, giving the Spanish crown and its empire to his son Philip II and transferring the imperial title and Austrian lands to his brother Ferdinand I .

This partition formalised the split between the Spanish and Austrian Habsburgs that would shape European politics for two centuries.