At first he followed a legal career at Pavia and Bologna, and when in 1499 he took his doctorate he was esteemed the most learned canonist in Europe.
He prudently began by republishing the anti-papal opinions of the famous canonist Gerson.
The document was received with universal applause, and Sarpi was immediately made canonist and theological counsellor to the republic. When in the following April the last hopes of accommodation were dispelled by Paul's excommunication of the Venetians and his attempt to lay their dominions under an interdict, Sarpi entered with the utmost energy into the controversy.
In the rest of Germany he found many supporters, chiefly professors in the Catholic faculty of theology at Bonn: among these were the famous canonist von Schulte, Franz Heinrich Reusch, the ecclesiastical historian Joseph Langen, as well as J.H.
A further revision of this code is stated to have been made by Constantine Porphyrogenitus, the son and successor of Leo, but this statement rests only on the authority of Theodorus Balsamon, a very learned canonist of the 12th century, who, in his preface to the Nomocanon of Patriarch Photius, cites passages from the Basilica which differ from the text of the code as revised by the emperor Leo.
It should be said, however, that most of these practices met with very considerable opposition both from councils and from theologians and canonists, amongst others from the English canonist William Lyndwood (Provinciale, lib.
He falls back on the definition of an earlier canonist that if the woman eats out of the same dish with the man, and if he takes her to church, she may be presumed to be his wife; if, however, he sends her to draw water and dresses her in vile clothing, she is probably a concubine (Provinciale, ed.