Unlike the present day, separation of powers between church and state were not clearly demarcated. A king's legitimacy was not easily secured unless he attempted to satisfy religious aims. For example, in the interest of staffing his government with qualified individuals, the Frankish king Charlemagne, who ruled from 768 to 814 A.D., sought to assimilate literate church officials into his government since few other members of his kingdom possessed similar degrees of literacy and professionalism. Furthermore, he issued legislation designed to manage secular as well as ecclesiastical affairs. This embrace of the Church by the State foreshadowed large-scale religious military campaigns of the 11th, 12th and 13th centuries that were waged by an affiliation of kingdoms in Roman Catholic Europe. During this era, the authority of European rulers to appoint religious officials was challenged by a series of popes, who sought to limit secular powers. Thus, while medieval kings were compelled to secure religious favor, they also bore the responsibility of championing secular power against a backdrop of papal criticism.
During the Middle Ages, royal power was lost almost as quickly as it was gained since networks of support were fragile and lines of succession to royal power were often poorly defined. For this reason, the power of medieval kings was based on their skills at securing local support, and kings bore on their shoulders the responsibility of developing alliances both with their subjects as well as other prominent rulers. In certain instances, kings were even henpecked by their wealthier subjects, such as in the case of King John of England, whose authority was limited in 1215 after he placed a royal seal on an English charter, referred to as the Magna Carta. Sociology Professor Cynthia J. Bogard of Hofstra University states, "The king was bound by custom, by his own law and by the necessity to practice self-restraint lest he be restrained by the community." As leaders of limited monarchies, medieval kings were participants in delicate balances of power, and their prerogatives were checked by others within their kingdoms.
Medieval kings spearheaded the military campaigns undertaken on behalf of their kingdoms. Practiced in the art of war, medieval kings were not merely figureheads. Early medieval monarchies arose in the wake of Rome's demise, as bold "barbarians" wrenched the remnants of power from the hands of bishops. Nevertheless, according to Stephen Morillo, author of "Warfare Under the Anglo-Norman Kings 1066-1135," warfare in the Middle Ages largely revolved around brash displays of force by leaders who secretly avoided encounters against equal measures of force. "Ravaging and plundering the land, building and besieging castles and actively avoiding battles were the normal, everyday activities of war, activities punctuated only in unusual and almost accidental circumstances by set piece engagements," maintains Morillo. Victorious monarchs were able to sidestep defeat even as they focused on defeating their adversaries.
Medieval kings who experienced success during their reigns were invariably skilled at consolidating military gains while making the most of limited resources. The only reason they experienced such success was because they knew how to administer affairs within their own governments. "Depending on the balance of power, political climate and personal agendas and ambitions, magnates were vulnerable to confiscation of lands, loss of title, imprisonment, exile and execution, while kings could be (and were) deposed," according to George W. Tuma, professor emeritus of English, and independent scholar Dinah Hazell.