Thanks largely to challenges regarding source material—its relative scarcity and wide dispersion across archives—medieval Castilian bishops have long been consigned to the historiographical periphery. In his new monograph, Kyle Lincoln aims to show that bishops were integral collaborators with the Castilian monarchy in the age of Alfonso VIII. He claims that their careful and largely successful efforts to bring their king and the popes closer together was critical to the Castilian church's lasting success. Medievalists of all stripes will benefit from Lincoln's close look at these mitered heads.

A Constellation of Authority consists of an introduction, seven concise studies of individual Castilian bishops, and a final chapter comparing Lincoln's findings with circumstances in other parts of Latin Christendom. The bishops he studies include Celebruno, a pioneer in tethering the fortunes of the archiepiscopate of Toledo to the monarchy; the high-ranking but incompetent Ramón II de Minerva; reforming, saintly figures like Martín Bazán and Julián ben Tauro; and Rodrigo de Finojosa, whose troubles in Sigüenza included killing a youth with his crozier during a fracas in the cathedral.

Lincoln's encyclopedic knowledge of medieval Castilian history does not cause him to miss the forest for the trees. Several patterns emerge across the individual case studies. First, bishops played an essential role in many critical aspects of Castile's affairs, including political and military stability. Lincoln credits the clergy with holding the kingdom together during Alfonso VIII's minority, and he highlights their participation in raids, sieges, and field battles such as Alarcos and Las Navas de Tolosa. Nearly all the Castilian clergy supported the patently illegal marriage between Berenguela and Alfonso IX of León, despite Innocent III's wrath, because they saw it as the only means of keeping peace between the two kingdoms.

Second, bishops generally pursued a twofold policy of extending their authority and control over other elements within their dioceses, particularly cathedral chapters, and of carefully balancing royal and papal interests. Martín López de Pisuerga took an aggressive approach toward the military orders and clerical institutions in his diocese, while simultaneously obtaining papal permission to absolve the infanta Berenguela of excommunication. His fatal assault with a crozier notwithstanding, Rodrigo de Finojosa fit the general pattern of a reforming bishop in the twelfth century. His Christian zeal coexisted with a shrewd eye toward advancement and a balanced use of both royal and pontifical interests to retrench his position. The balancing of these interests sometimes required deflecting inquiries from outside the peninsula. Papal legations often raised the issue of the Castilian clergy's sexual improprieties, yet bishops fought for the prerogative to handle—or not handle—such matters on their own.

Third, formal education played an increasingly important role in cultivating clerical talent. León and Castile had numerous monastic studia and scriptoria, such as San Millán de la Cogolla and Santiago de Compostela, but their significance was soon surpassed by the new studium at Palencia. St. Dominic, who was recruited from there to help reform the chapter of Osma around 1191, was one of its many successful graduates. At least thirty-eight canons in Castile employed the title of magister during this period, leading Lincoln to identify them as participants in the “twelfth-century renaissance.” This emphasis on education marked a subtle shift away from the policy of elevating men to the episcopate based on the nobility of their line.

Occasionally Lincoln's assessments of bishops’ careers leave unanswered questions. For example, he implies that Ramón II de Minerva has been unfairly characterized as corrupt and obsolete, but he provides little in the way of evidence or argument that would rehabilitate the bishop. Lincoln might also have explored more thoroughly the early career of St. Dominic before he became the property of the Order of Preachers.

Constellation's final chapter compares the bishops of Alfonso's reign with the higher clergy in other regions of Latin Christendom. Lincoln concludes that the general patterns were basically the same; contrary to the old tourist slogan, Spain is not different. His argument for the unity of Latin Christendom during the twelfth and thirteenth centuries echoes Robert Bartlett's The Making of Europe: Conquest, Colonization, and Cultural Change, 950–1350 (Princeton, NJ: Princeton University Press, 1994). Lincoln's comparative approach is inchoate rather than exhaustive, but it nevertheless contributes to the study of the medieval episcopate broadly speaking.

A Constellation of Authority is a significant accomplishment from a promising young scholar. By piecing together the evidence of numerous cases into a coherent picture amidst the relative absence of existing literature, Lincoln demonstrates considerable acumen as well as intellectual courage. Readers will come away with an increased appreciation of the crucial role that bishops played in the social and political order of Castile, and indeed of all Latin Christendom, in the age of Alfonso VIII.