Hosius, bishop of the city of Corduba, said: A prevalent evil, or rather most mischievous corruption must be done away with from its very foundations. Let no bishop be allowed to remove from a small city to a different one: as there is an obvious reason for this fault, accounting for such attempts; since no bishop could ever yet be found who endeavoured to be translated from a larger city to a smaller one. It is therefore evident that such persons are inflamed with excessive covetousness and are only serving ambition in order to have the repute of possessing greater authority. Is it then the pleasure of all that so grave an abuse be punished with great severity? For I think that men of this sort should not be admitted even to lay communion. All the bishops said: It is the pleasure of all.
Bishop Hosius said: A prevalent evil and mischievous corruption must be done away with from its foundation. Let no bishop be allowed to remove from his own city to another. For the reason of such attempts is manifest, since in this matter no bishop has been found who would remove from a larger city to a smaller one. It is therefore evident that these men are inflamed with excess of covetousness, and are serving ambition and aiming at the possession of power. If it be the pleasure of all, let so great an evil be punished right harshly and sternly, so that he who is such shall not even be admitted to lay communion. All with one accord answered: Such is our pleasure.
Ancient Epitome of Canon I.
No bishop is to be found passing from a smaller to a greater city. If anyone should move from an humble to a more important see, he shall be excommunicated through his whole life as proud and grasping.
(Dissert. in Synod. Sard., § II.  )
What Peter de Marca says (De Concordia Sacerdotii et Imp., Lib. V., cap. iv.), "Hosius presided over" this council as legate of the Roman bishop, rests upon no solid foundation, and no trace of any such legation is found in Athanasius or in any of the other writers who treated of this synod. Moreover such a thing is contrary to the form of subscription used. For of those who signed the first is Hosius, and Athanasius designates him simply as "from Spain," without any addition; and then next he mentions "Julius of Rome, by Archidamus and Philoxenus, his presbyters," etc. What is clearer than that, by the testimony of Athanasius, Julius was present by these two presbyters only, and that they only were his legates or vicars, who in his room were present at this synod?
The first part of this canon is found in the Corpus Juris Canonici; Raymund's Decretales, De Clericis non residentibus, Cap. ii.
 The whole of this Dissertation is worthy of careful study.