As an adult, Barlow went to France to be educated with his younger brother Edward at the English College in Douai.
)[2] Wishing to become a Benedictine, Barlow joined the Spanish congregation in 1604 at which time he was given the religious name by which he is now known, being professed at Cella Nueva in Galicia in 1605.
In 1611 he transferred to join the community of English monks at the Priory of St Gregory the Great in Douai (now Downside Abbey in England), where he was made its prior in 1614.
Beyond a circular letter to the English Benedictines about their relations with the Vicar Apostolic of England, none of his writings survive.
According to Ralph Weldon, Barlow was looked on as a leading theologian and canonist; and effectively opposed Richard Smith, who claimed leadership of the English Roman Catholics, in becoming Bishop of Chalcedon.
Weldon added that after his death a bishop offered the Benedictines of Douai an establishment if they would give him Rudesind's writings, "but in vain they were sought for, for they were destroyed by an enemy".