The kings of France had traditionally been noted for their closeness to the Church and to the Pope. They were fervent patrons of reformed monasticism in the 12th and 13th centuries AD and were major figures in the Crusades. The greatest king in this tradition was Louis IX (1226-1270) – St Louis. Louis was famed for his justice, piety and crusading fervour as well as his religious relics which included the Crown of Thorns, a treasure of the French kings.

French monarchs expected to control much religious life in their land and make use of Church resources. This, when combined with new attitudes to royal authority, led to a shift in relations with the papacy. Louis’ grandson, Philip IV (reigned 1285-1314) challenged Pope Boniface VIII’s claim to spiritual supremacy over a divinely appointed king. The move of the papacy from Rome to Avignon, France, and the election of a series of popes relatively compliant to French wishes, created a new situation in the 14th century.

Around the 1370s, as royal power weakened during the Hundred Years’ War, French kings began to use the title ‘rex Christianissimus’ – the Most Christian King. The French kings renewed their alliance with the papacy to oppose a movement in the French Church aimed as increasing the independence of bishops from papal and royal control.