Discontent had been brewing for years before the Revolt of the Comuneros. The second half of the 15th century saw profound political, economic, and social changes in Spain. Economic growth created new urban industries and offered a route to power and wealth not tied to the aristocracy. Support from these urban elites was critical to Ferdinand and Isabella's centralization of power, and they acted as a counterweight to the landed aristocracy and the clergy.
However, with Isabella I's death and Joanna's accession in 1504, this alliance between the national government and the budding middle class faltered. The Castilian government decayed with each successive administration, becoming rife with corruption. Joanna's husband, Philip I, reigned briefly; he was replaced by Archbishop Cisneros as regent for a short time, and then by Isabella's widower Ferdinand who ruled from Aragon. Ferdinand's claim to continue ruling Castile as regent was somewhat tenuous after Isabella's death, but no plausible alternatives existed as the sovereign, their widowed daughter Joanna, was mentally unfit to reign on her own. The landed nobility of Castile took advantage of the weak and corrupt Royal Council to illegally expand their territory and domain with private armies while the government did nothing. In response, the towns signed mutual defense pacts, relying on each other rather than the national government.
The budgets of both Castile and Aragon had been in poor condition for some time. The government had expelled the Jews in 1492 and the Muslims of Granada in 1502, moves that undercut lucrative trades and businesses. Ferdinand and Isabella had been forced to borrow money to pay troops during and after the Reconquista, and Spanish military obligations had only increased since then. A large number of troops were required to maintain stability in recently conquered Granada, threatened by revolt from the maltreated moriscos (former Muslims who had converted to Christianity) and frequent naval raids from Muslim nations along the Mediterranean. Additionally, Ferdinand had invaded and occupied the Iberian part of Navarre in 1512, and forces were required to garrison it against Navarrese revolts and French armies. Very little money was left to pay for the royal army in Castile proper, let alone service foreign debts. The corruption in the government since Isabella's death only made the budget shortfalls worse.
Succession of Charles
In 1516, Ferdinand died. The remaining heir was Ferdinand and Isabella's grandson Charles, who became King Charles I of both Castile and Aragon in coregency with his mother Joanna. Charles was brought up in Flanders, the homeland of his father Philip, and barely knew Castilian. The people greeted him with skepticism, but also hoped he would restore stability. With the arrival of the new king in late 1517, his Flemish court took positions of power in Castile; young Charles only trusted people he knew from the Netherlands. Among the most scandalous of these was the appointment of the twenty-year-old William de Croÿ as Archbishop of Toledo. The Archbishopric was an important position; it had been held by Archbishop Cisneros, the former regent of the country. Six months into his rule, discontent openly simmered among rich and poor alike. Even some monks began to agitate, denouncing the opulence of the royal court, the Flemish, and the nobility in their sermons. One of the first public protests involved placards posted in churches, which read:
You, land of Castile, very wretched and damned are you to suffer that as noble a kingdom as you are, you will be governed by those who have no love for you.
With the unrest growing, Charles' paternal grandfather Holy Roman Emperor Maximilian I died in 1519. A new election had to be held to choose the next emperor. Charles campaigned aggressively for the post, vying with King Francis I of France to bribe the most prince-electors. Charles I won the election, becoming Emperor Charles V and cementing the power of the House of Habsburg. He prepared to head to Germany to take possession of his new domains in the Holy Roman Empire.
New taxes: The Cortes of Santiago and Corunna
Charles had already stressed the treasury to its limit with his extravagant Flemish court, and over 1 million florins were spent in bribes for the election. Taxes[note a] had to be raised to cover the debt, but any new taxes had to be approved by the Cortes (Castile's own parliamentary body). Thus, in late March 1520, Charles convened the Cortes in Santiago de Compostela. Charles ensured the Cortes would only have limited power, and further attempted to stack the Cortes with pliable representatives he could bribe. Support for the opposition only increased in response, and the representatives demanded that their grievances be heard first before any new tax was granted.
A group of clerics soon circulated a statement in protest of the king. It argued three points: any new taxes should be rejected; Castile should be embraced and the foreign Empire rejected; and if the king did not take into account his subjects, the Comunidades themselves should defend the interests of the kingdom. It was the first time where the word comunidades (communities, communes) was used to signify the independent populace, and the name would stick to the councils later formed.
At this point, most of the members of the Cortes in Santiago intended to vote against the king's requested duties and taxes, even with the Cortes stacked with royalists. In response, Charles decided to suspend the Cortes on April 4. He convened them again in Corunna on April 22, this time getting his program passed. On May 20, he embarked for Germany, and left as regent of his Spanish possessions his former tutor, Adrian of Utrecht (better known as the future Pope Adrian VI).