Baring-Gould’s sources: Molanus, Wyon, Menardus, Miræus in his 'Belgian Saints,' and Saussaye in his Gallican Martyrology. Authority:—A life, probably by Hucbald of Elnone (907), derived from various earlier accounts and traditions.

S. Eusebia was the eldest daughter of S. Adalbald, of Douai (Feb. 2nd) and S. Richtrudis. Probably on the occasion of the assassination of her father, she was sent to the convent of Hamage, which was governed by her grandmother, S. Gertrude. On the death of S. Gertrude, Eusebia, at the age of twelve, was elected abbess of Hamage, according to a custom of the time, which required abbesses, if possible, to be of noble birth, so as to secure for the convent protection from powerful families in times of difficulty or war. But S. Richtrudis, who had become abbess of Marchiennes, thinking that the girl was far too young to manage the community, and that under her light hand grave disorders might prevail, peremptorily ordered Eusebia to come with all her nuns to Marchiennes. Eusebia hesitated, but when the orders were repeated, she reluctantly obeyed, and with all the community, bearing the body of S. Gertrude, she came to Marchiennes, where they were received by a procession with lights and incense. Eusebia was not happy in her new home, and sighed for Hamage. During the night, when every one slept, she was wont to steal out, barefooted, and run to the deserted convent, to watch and pray over the home of her infancy, fragrant with memories of a beloved guide and spiritual mother. Richtrudis, hearing of these nocturnal excursions, and not approving of them, ordered the child-abbess a sound flogging, and asked her brother Maurontius to administer it. Eusebia writhed and danced about under the correction, to elude the blows, and in so doing ran against the point of the sword of Maurontius, which slightly wounded her side. According to a popular legend, which the historian records merely as such, one of the twigs of the birch with which Eusebia was corrected, rooted itself on the spot where it had fallen, and grew up into a stately tree.

Richtrudis, seeing that her child continued bent on returning to Hamage, consulted the bishop, who advised her to yield. Accordingly Eusebia and her community went back to the deserted convent, and she governed it with prudence, living in piety, till the day of her death. She was buried in the church of the Apostles, at Hamage; but the body was afterwards translated to Marchiennes.

In Belgium she is called S. Isoie, or Eusoye.