Upon becoming the joint monarchs of Castile and Aragon, one of the main challenges that Ferdinand and Isabella faced was to extend the crown's authority over the Iberian peninsula thus increasing the stability of the kingdom and power of the crown. This was a daunting task, especially given the power of grandees such as Mendoza and Carillo at the time. The Catholic kings had some considerable success in consolidating royal authority, but there were limitations on this success and compromises were made; especially in the kingdom of Aragon. This will largely be an essay on Castile, as Castile was the dominant body in Spain, but I will consider the substantial differences in the administration and other areas of Aragon which, arguably, meant that the monarchs were considerably less successful at consolidating their authority there.…
