The Royalist side fought to uphold the existing government of King Charles I (Carlos I). Along with Charles, the government was led by the Regent, Cardinal Adrian of Utrecht (Adriano de Utrecht). Charles' departure for Germany to take up his recently acquired position as Emperor Charles V of the Holy Roman Empire (There were four Charles before him as Holy Roman Emperor, but none as King of Castile and Aragon) helped provoke the Revolt; he was seen as having broken his promise to leave a Castilian in charge of the country, for Adrian was Flemish.

Despite being in Germany for the duration of the Revolt, Charles nevertheless played an important role in quelling it via communication and orders to Regent Adrian. One of the most influential decisions Charles made was to appoint two new co-regents to govern Castile: the Constable of Castile, Íñigo Fernández, and the Admiral of Castile, Fadrique Enríquez.

Royal Council and Advisers: The Royal Council had functionally run the country during the period following King Philip I. However, they were not well regarded among the common people; the government often ineffectively stood by while nobles illegally expanded their domain through threats of force. Corruption ran rampant, and the government fell into debt. The Council's President, Antonio de Rojas, was widely hated.

Still, disrespect of the Royal Council paled next to the distaste of the retinue of Flemish advisers that Charles brought with him into Spain. William de Croÿ, sieur de Chièvres (Guillermo de Croÿ, señor de Chièvres) had managed much of Charles' upbringing in Flanders and had not taught him overly much statecraft; by doing so he forced Charles to rely on him for advice. Many of these Flemish advisers proceeded to enrich themselves with funds from the Castilian treasury. William de Croÿ became Treasurer of Castile, a position which he later sold to Alvaro de Zúñiga, duke of Béjar, for 30,000 ducats. William had full control over who was appointed to administrative positions to Spain's fledgling colonies in the West Indies, and appointed friends of his to positions such as Bishop of Cuba. He promised rich fiefs to Laurent de Gorrevot (another prominent Flemish adviser) in Cuba and the Yucutan (later annulled), permitted the importation of 4,000 African slaves to the Indies, and sold rights to a syndicate for 25,000 ducats. William also managed to get his twenty-year-old nephew (named William de Croÿ as well) appointed Archbishop of Toledo, an extremely unpopular act of nepotism. Jean Le Sauvage served as chancellor and controversially presided over the Cortes of Valladolid in 1518. Le Sauvage obtained in December 1517 the right to collect duties on the export of almonds and dried fruits, a position formerly held by the ruler of Granada. Le Sauvage leased this privilege to Fernando de Córdoba for nine years for 168,000 ducats.

Military commanders: Rodrigo Ronquillo, who led the ill-fated expedition to Segovia to punish the murder of the legislator who voted for the king's tax at the Cortes of Corunna.
Antonio de Fonseca, the captain-general of the Castilian army who went to Medina del Campo to seize the royal artillery, but was driven off by the civilians.
Antonio de Zúñiga, the prior of the Order of St. John.

Formation Date 1500
Conflict Name Initiation Year Termination Year Total Killed Total Casuality
Revolt of the Comuneros 1520-1521 1520 1521 unknown unknown