Peter, a learned Italian, who flourished in the 16th century. He was well versed in the Greek and Latin tongues, and wrote some pieces of eloquence which met with great approbation. He was corrector of the press a considerable time for Aldus Manutius, and is entitled to a share in the praises given to the editions of that learned printer. He published a treatise concerning banishment, which contained so many fine passages intermixed with others quite the reverse, that it was thought he had tacked to somewhat of his own, several fragments of a treatise of Cicero de Gloria; and that afterwards, in order to save himself from being detected in this theft, he burnt the manuscript of Cicero, the only one extant. Paulus Manutius, in his commentary upon the words of Cicero, Libram tibi celeriter mittam de gloria," "I will speedily send you my treatise on Glory," has the following passage relating to this affair: "He means Aleyonius (says he) his two books on Glory, which were handed down to the age of our fathers; for Bernard Justinius, Alderman, in the index of his books, mentions Cicero's Gloria.

This treatise, however, when Bernard had left his whole library to a monastery, could not be found, though sought after with great care: nobody doubted but Peter Aleyonius, who, being a physician to the monastery, was entrusted with the library, had falsely stolen it. And truly, in his treatise of Banishment, some things are found interspersed here and there, which seem not to favour of Aleyonius, but of some higher author." The two orations he made after the taking of Rome, wherein he represented very strongly the injustice of Charles V., and the barbarity of his soldiers, were excellent pieces. There is also an oration ascribed to him, on the knights who died at the siege of Rhodes.