He first appeared in the eight-part saga Storia e gloria della dinastia dei paperi (History and glory of the Duck Dynasty) by Guido Martina, Romano Scarpa, Giorgio Cavazzano and Giovan Battista Carpi, first published between April 5, 1970 and May 24, 1970.
In any case according to his origin story Pah-Peh-Rheo was born an Egyptian. He was supposedly a non-royal uncle to a Queen of Egypt who herself was the great-grandmother of Cleopatra VII of Egypt. (This is the first in a series of anachronisms, discussed brefly below).
When the crypt finished, Pah-Peh-Rheo and four non-royal nephews of his undertook the duty of transporting one thousand sacks of gold disguised as cameleers. On the road to the Pyramid they were stopped and questioned by four desert bandits, depicted as distant ancestors of the Beagle Boys. Pah-Peh-Rheo managed to convince them that his caravan was consisted only of carriers of infectious disease, making their last trip. The bandits fled in order to avoid contacting the disease and the caravan continued on its way. They successfully managed to transfer their cargo in the crypt. Unbeknown to the others, Pah-Peh-Rheo and his mechanic had arranged for one thousand sacks of desert sand to be placed in the actual chamber of the Pyramid. This was intended to fool anybody who would come searching for the treasure. With their mission finished they all returned to the palace in Alexandria.
Sometime later though, the leader of the desert bandits conceived a plan to abduct the Queen and have Pah-Peh-Rheo exchange her for the contents of his treasury. He sent the Queen a coffin of fruit, supposedly as a gift from the fruit merchants guild. But when the "gift" was delivered to the Queen's chambers, two of the bandits emerged for it. They quickly managed to subdue the Queen and her present servants. Then they rolled a carpet around her and managed to carry her out of the palace and to their lair. Soon enough a message with their demands was delivered to Pah-Peh-Rheo. Deciding to play along he led the bandits to the Pyramid and they delivered him the Queen. Pah-Peh-Rheo, the Queen, his four nephews and his mechanic fled by boat. Soon enough the bandits found that the sacks he pointed them to contained only sand. They gave chase by boat but by use of a simple mirror reflecting sunlight to his eyes and dazzling them, their leader lost command of the boat and crashed to a nearby reef. With the bandits now convinced that the Pyramid contained only sand, Pah-Peh-Rheo also led his allies to believe that he intentionally wanted to draw attention to the Pyramid while the treasure was transported elsewhere. The Pyramid and the treasure below it where so left undisturbed for centuries to come.
His relative peace would soon come to an end. The desert bandits believed him to have escaped with the entire royal treasury and were still trying to locate him. They eventually succeeded in tracing him to Rome. Four of them were sent to further locate him and the treasure. Their leader had instructed them to come in contact with an old acquaintance of his. The latter (depicted as a distant ancestor of Black Pete) was a former criminal and gladiator but by that time had gained a reputation as a lanista. He was rejoiced to hear of his old friend and even more so to learn of the treasure.
The bandits proceeded in explaining that Pah-Peh-Rheo was last reported to be hiding in Rome under an assumed name and operating a tavern by the Tiber river. The old gladiator in turn explained that there were more taverns by the Tiber than fleas on a dog. Informed that Pah-Peh-Rheo was a miser by reputation, he thought of Petronius Paperonius. He accompanied the bandits to Petronius' tavern and they easily recognized the latter to actually be Pah-Peh-Rheo.
The five agreed to sleep early and return to the tavern at night as burglars. But the old gladiator planned to betray his new allies. While they slept, he visited a centurion of the Praetorian Guard. The centurion (depicted as a distant ancestor of John D. Rockerduck) had reportedly acted as his partner in a number of shady but profitable schemes and was also interested in this one. He and his men would wait for the burglars to enter the tavern and find the treasure. Then they would procceed to arrest them all and gather the treasure as evidence. Finally the centurion and the gladiator would share the treasure among them.
But events did not go according to their plan. The burglars found the golden coins in the tavern's cellar, contained in large wooden barrels but caused enough noise to alert Petronius and his four nephews. They arrived armed with clubs and a fight started. The centurion chose this opportunity to enter and arrest them all. He informed the old gladiator that their alliance had ended and no sharing would occur. He also revealed himself to be a personal enemy of Petronius. He accused the later of being a traitor to the Roman Empire and promised him death by capital punishment.
The centurion wanted to ensure this conclusion with a signed order by Roman Emperor "Pippus Caesar Augustus" (Caesar Augustus depicted as a distant ancestor of Goofy). But he did not want the latter to closely examine the case and discover the treasure. He soon formed another scheme. By morning the centurion had secretly organized a riot in Rome. Rioters were in protest of the Emperor's inactivity as of late. The centurion alerted the Emperor to the event. The later verbally commented on his loyalty. He confessed that the reason behind this inactivitie was the lack of sufficient funds to organize his legions, finance new campaigns of conquest or even finish the construction of the Colosseum.
The centurion advised the offering of entertainment to the crowds. He then offered the Emperor a list of entertainment events and stated that it was ready to be signed. The Emperor stated that he was illiterate and asked the centurion to read the list aloud.
The Emperor listened to the list and seemed content with it. He proceeded in signing it. The centurion then offered to personally make the announcement to the public. But the Emperor would not hand him the list. He then revealed that Petronius' three youngest nephews had escaped custody and contacted him. He asked them to read the list which actually was a command to throw Petronius and his eldest nephew to the lions. Having attempted to fool the Emperor, the centurion was arrested for treason. Petronius and his elder nephew were released. Petronius soon learned that the price of his release was to finance a new campaign with his treasure.
During the 14th century, a descendant of his named in Italian Paperon McPaperon (Scrooge McDuck the Elder) had settled in Edinburgh. By 1392, he acted as a favorite of the Queen of Scotland and relative of his "Trisnonna Papera" (Great-Great-Grandma Duck, (historically at the time King Robert III of Scotland reigned and his Queen consort was Annabella Drummond) and a life-long enemy of Duke McRockerduck. He reportedly owned the Kingdom's lead Mines and directed the Royal Mint. He had also learned of a family tradition stating that every century since Petronius' death and on an April night, a ghost of illusion of him appeared... bathing in his hoarded Roman gold.
The descendant settled in Loch Ness and waited for the appearance. It occurred on April 30, 1392 and led him to discover the treasure. He then proceeded in abandoning Scotland for the Iberian peninsula. He settled in Seville, Andalusia and established a Spanish branch of the family that would spread Paperonius' influence and star in the further chapters of Storia e gloria della dinastia dei paperi (History and glory of the Duck Dynasty).
Again, the Colosseum was built under the Emperor Vespasian, who reigned from 70 AD to 79; and all the early Roman Emperors could read both Greek and Latin (Claudius read Etruscan too). However, the majority of Roman Emperors were not ducks.
Petronius' centennial reappearances would presumably have occurred in 1392, 1292, and so on; which would place his death in 9 BC, or possibly 92 AD. This would make him much more than a century old.