He is known only from his translation of the writings of Pseudo-Dionysius from Greek into Latin.
Until this point, theologians in the Latin-speaking West had had to read Dionysius using the ninth-century translation made by Johannes Scotus Eriugena, which was not easy to understand.
In contrast, Sarrazin produced a clearer version which was used by Albert the Great and Thomas Aquinas, and had a significant effect on later European mystical writing.
John dedicated two of his translations to the abbot of the monastery of Saint-Denis, near Paris.
By his own account, he toured Greece for research purposes and was excited by the work of John of Salisbury.