"Daventriensis" was raised by his uncle, Johannes von Grätz, in Deventer. In 1501 he left to pursue philosophical studies at the University of Cologne.
After joining Kyuk Burse, Ortwin became licensed in 1505, attained Masters level in 1506 and became an Art Professor in 1507. He supplemented his salary by proofing documents for Quentell printers and wrote introductions and poetic dedications in the volumes of classical authors of the Middle Ages.
Ortwin was a follower of Hegius and Peter of Ravennal, a Humanist, and boasted many prominent, intellectual friends. Because Ortwin sided with the Cologne University theologians and the Dominicans during the Reuchlin controversy, he found himself the subject of aggressive attacks from Hermann von den Buschel and the younger generation who were not pleased with his translations of the Jewish convert, Pfefferkorn.
Ortwin had at that time just finished a literary tournament with von dem Busche, and had been made the laughing-stock of the literary world by the venomous Epistolae obscurorum virorum, letters that were addressed to him.  His adversaries succeeded in vilifying him on both moral and scientific grounds, denouncing his Latin and Greek scholarship and portraying him as a drunkard and worse. Ortwin made no response until Pope Leo X excommunicated the author, readers, and distributors of the Epistolary (1517). After his weak and ineffective defense, entitled Lamentationes obscurorum virorum, his damaged reputation remained distorted for centuries. In 1520 he was ordained to the priesthood and thereafter focused entirely on literary work.
The magnum opus of his literary activity is: Fasciculus rerum expetendarum ac fugiendarum (Cologne, 1535), a collection of sixty-six more or less weighty treatises of various authors on ecclesiastical and profane history, dogma and canon law, compiled to expose the noxious elements in the Church's organism, and prepare a way for a future council to remedy them. It has been wrongly claimed that this work, put on the Index on account of its anticlerical tendency, was not from the pen of Gratius.
- Or Orthvinus, Ortuin, or Hardouin. He is also known as Hardouin de Graes or …de Graetz in French.
- The Northern Renaissance And The Background Of The Reformation
- "Ortwin Gratius". Catholic Encyclopedia. New York: Robert Appleton Company. 1913.
- Friedrich Wilhelm Bautz (1990). "Gratius (van Graes), Ortwin". In Bautz, Friedrich Wilhelm. Biographisch-Bibliographisches Kirchenlexikon (BBKL) (in German) 2. Hamm: Bautz. cols. 290–291. ISBN 3-88309-032-8.