French ecclesiastical historian and Cistercian abbot, who steered cleverly through contemporary doctrinal controversies.

As a young man Fleury practiced law in Paris for nine years and became a protégé of Bishop Jacques-Bénigne Bossuet. He then turned to the priesthood, becoming ordained in 1669, and later became a tutor at court. In 1716 he was made confessor to the young Louis XV, as being “neither Jansenist, nor Molinist, nor Ultramontanist, but Catholic.” His 20-volume Histoire ecclésiastique (1690–1720) is the first large history of the Christian church (Fleury's contribution came down to 1414, and others later completed the history down to 1778). However, because Fleury was sympathetic toward Gallicanism (an ecclesiastical doctrine advocating restriction of papal power), his works were placed on the Roman Catholic Index of Forbidden Books.