Towns Weakened
Although the impetus for rebellion came largely from Charles V and his mis-government, there was a further, historical, tension behind the revolt. The long standing rivalry between the towns and nobility of Castile shifted in the fifty years before 1519, as the towns lost a position of superiority to the growing domination of the aristocracy. In the 1470's Queen Isabella of Castile had formed an alliance with the towns against the nobility, whereby the towns would act as a league, form a general militia and enforce the laws. This was the 'Council of the Holy Brotherhood', and it offered political, financial and - through the militia - military support to the crown. However, in 1498 the Brotherhood was disbanded, and the towns stripped of their new powers and position.
Rise of the Nobility
The crown then shifted back to the nobility, courting their support, and the aristocracy took this chance to reassert themselves over the towns, expanding onto their lands and into their politics. Although the grandees are associated primarily with rural estates, noble families lived, and quarrelled, in the cities. Indeed, family rivalries were present in almost every Spanish town, dominating the local social and political atmosphere; many of these groups were related to the country dwelling grandees, while others were purely urban families. The town/grandee rivalry had always been complicated by the presence of these internal clashes, but they could be advantageous to the nobility. When Cisneros attempted to raise a militia through the towns during his regency of 1516 - 17, the grandees were able to invoke great opposition through their family connections.
Towns under Threat
In 1516 the towns felt threatened by an aristocracy keen to dominate or erode them, and the vacuum created by an absent king invited only further conflict: the unrest during Charles' initial absence set an important, but historically repetitive, precedent that helped spur the revolt. Additionally, royal authority and administration were now maintained in the towns through officials called 'corregidores'. However, these individuals were either unable to stop the aristocracy corrupting legal and fiscal procedures, or they were themselves corrupt, bias in favour of particular families. By 1520 the situation had worsened for the towns: not only had Charles done nothing to improve their position, but he had sought to increase taxes and ride roughshod over the Cortes, further undermining their representation and power.The loss of royal favour caused resentment in the towns, and as the years passed this bitterness grew, transforming the memory of Isabella's reign into a myth of glorious times when the towns were treated fairly, a golden age of urban government. These ideas sharpened, some may say corrupted, the contrast with later royal governments, feeding the towns' dislikes. Charles may have caused upset across Spain, but in Castile he inflamed a strong and long-running conflict and the towns, the side which was losing power, exploded into rebellion against both the king, and the government of Castile itself.
