St. John Eudes (1601–1680) was an Oratorian, parish-mission preacher, and founder of two religious congregations — the Society of Jesus and Mary (Eudists) and the Congregation of Our Lady of Charity (the Refuge). For nearly half a century he preached over 110 parish missions across northern France, particularly in Normandy.
From around 1645 he began promoting devotion to the Heart of Mary, calling it 'the abridgement of all wonders.' In the 1670s he extended his devotion to the Heart of Jesus, and in 1672 — a year before Margaret Mary Alacoque's first major apparition at Paray-le-Monial — he composed and obtained ecclesiastical approval for the first formal liturgical Mass and Office of the Sacred Heart. Eudes thus provided the foundational theological and liturgical groundwork on which the Margaret Mary apparitions would later build. Pope Pius X named him 'father, doctor, and apostle of the liturgical worship of the Sacred Hearts of Jesus and Mary'; canonised by Pius XI in 1925.