The corregidores were Castilian royal officials who functioned as mayors and superior judges in the provinces, cities, towns, and villages they were sent to oversee. At the head of urban militias they took part in the War of Succession and the Granada War. The corregidores thus had significant dealings with the peasantry, urban masses, the merchants, the nobles, the aristocracy, the officials of the Inquisition. Through its study of their many varied duties, this book offers a panoramic view of Castile during the late medieval and Renaissance eras. Despite their importance, a major study has never before been devoted entirely to their activities during the reign. This study also incorporates a major effort at periodisation of Isabella's reign, the first attempted in modern times. Overall, the book offers a tripartite dissection of the queen's career in power and an assessment of the differing states of the operations of corregidores over her three decades.