Eadmer (or Edmer) was born shortly before the Norman conquest of England in 1066. He became a monk in the Benedictine monastery of Christ Church, Canterbury, where he first met Anselm and became his disciple, then his friend. When Anselm became archbishop of Canterbury in 1093, Pope Urban II appointed Eadmer to be his director. In 1120 he was named bishop of St Andrews in Scotland but as the Scots would not recognize the authority of the see of Canterbury he was never consecrated, and soon afterwards he resigned his claim to the bishopric. He died in the year 1126 or shortly after.
Eadmer is credited with influencing the spread of the doctrine of the Immaculate Conception of the Blessed Virgin Mary in the West, when he defended popular traditions in his De Conceptione sanctae Mariae. The origins of the dogma lay in the East and had been long-established in Greece. The idea began to gain currency in England in the opening decades of the 11th Century and had become the subject of liturgical veneration and a feast day (8 or 9 December) at Canterbury, Worcester and Winchester by about 1030. Eadmer argued that Christ's human perfection required that his Mother should be also without sin.