The land of Solesmes was long consecrated to God, according to the Acts of the bishops of Le Mans. St. Thuribus, in the fifth century, organized public worship in the Gallo-Roman villa de Solesmis. By the beginning of the ninth century, this property belonging to the Church of Le Mans was held as a benefice for a vassal of Charlemagne's court. Soon, the church and its surroundings were put in the hands of Raoul de Beaumont, Vicount of Le Maine following a succession of Norman raids. In order to fortify their border against Anjou; the counts of Le Mans established Geoffroy, Raoul's own brother, as lord at Sablé.
Raoul gave Solesmes to Geoffroy, who wished to donate it to the monks of la Couture by a charter conjecturally dated October 12, 1010. The monastery of Solesmes reckons this as the date of its foundation.
Nothing much is known about the monastery during the twelfth and thirteenth centuries, but the peace and prosperity of the era allowed the prior, Guillaume Patry, to have the dam in the river Sarthe reconstructed so as to properly power the two mills placed there at the time.
Still, difficult times were in the offing. Some time before 1365, a house on the Isle of Sablé was donated to the monks and soon served as a place of refuge. (This was the logis de Solesmis where, much later, Dom Guéranger, the future restorer of the Benedictine Order in France, lived as a boy.) In 1375, Solesmes experienced a first taste of the sufferings brought on by the interminable Hundred Years War. Fifty years later, the English occupied the countryside, burning and destroying the monastery and leaving the town in ruins, abandoned and resourceless. In 1491, and again in 1497, Jean de Nemous was obliged to make considerable donations so that the monks could fulfill their various liturgical and devotional duties. Among them was the daily obligation, after the office of Prime, of the King's Mass, established in 1408 by Louis II of Anjou, king of Jerusalem and Sicily.