As we have stated, the chapels consecrated to Isis were demolished in the year 48 B. C. After Cæsar's death, the triumvirs decided in 43 B. C. to erect a temple in her honor out of the public funds, undoubtedly to gain the favor of the masses. This action would have implied official recognition, but the project appears never to have been executed. If Antony had succeeded at Actium, Isis and Serapis would have entered Rome in triumph, but they were vanquished with Cleopatra; and when Augustus had become the master of the empire, he professed a deep aversion for the gods of his former enemies. Moreover, he could not have suffered the intrusion of the Egyptian clergy into the Roman sacerdotal class, whose guardian, restorer and chief he was. In 28 B. C. an ordinance was issued forbidding the erecting of altars to the Alexandrian divinities inside the sacred enclosure of the pomerium, and seven years later Agrippa extended this prohibitive regulation to a radius of a thousand paces around the
city. Tiberius acted on the same principle and in 19 A. D. instituted the bloodiest persecution against the priests of Isis that they ever suffered, in consequence of a scandalous affair in which a matron, a noble and some priests of Isis were implicated.
All these police measures, however, were strangely ineffectual. The Egyptian worship was excluded from Rome and her immediate neighborhood in theory if not in fact, but the rest of the world remained open to its propaganda.[[27]]
With the beginning of the empire it slowly invaded the center and the north of Italy and spread into the provinces. Merchants, sailors, slaves, artisans, Egyptian men of letters, even the discharged soldiers of the three legions cantoned in the valley of the Nile contributed to its diffusion. It entered Africa by way of Carthage, and the Danubian countries through the great emporium of Aquileia. The new province of Gaul was invaded through the valley of the Rhone. At that period many Oriental emigrants went to seek their fortunes in these new countries. Intimate relations existed between the cities of Arles and Alexandria, and we know that a colony of Egyptian Greeks, established at Nimes by Augustus, took the gods of their native country thither.[[28]] At the beginning of our era there set in that great movement of conversion that soon established the worship of Isis and Serapis from the outskirts of the Sahara to the vallum of Britain, and from the mountains of Asturias to the mouths of the Danube.
The resistance still offered by the central power could not last much longer. It was impossible to dam in this overflowing stream whose thundering waves struck the
shaking walls of the pomerium from every side. The prestige of Alexandria seemed invincible. At that period the city was more beautiful, more learned, and better policed than Rome. She was the model capital, a standard to which the Latins strove to rise. They translated the works of the scholars of Alexandria, imitated her authors, invited her artists and copied her institutions. It is plain that they had also to undergo the ascendancy of her religion. As a matter of fact, her fervent believers maintained her sanctuaries, despite the law, on the very Capitol. Under Cæsar, Alexandrian astronomers had reformed the calendar of the pontiffs, and Alexandrian priests soon marked the dates of Isis holidays upon it.
The decisive step was taken soon after the death of Tiberius. Caligula erected the great temple of Isis Campensis on the Campus Martius probably in the year 38.[[29]] In order to spare the sacerdotal susceptibilities, he founded it outside of the sacred enclosure of the city of Servius. Later Domitian made one of Rome's most splendid monuments of that temple. From that time Isis and Serapis enjoyed the favor of every imperial dynasty, the Flavians as well as the Antonines and the Severi. About the year 215 Caracalla built an Isis temple, even more magnificent than that of Domitian, on the Quirinal, in the heart of the city, and perhaps another one on the Coelian. As the apologist Minucius Felix states, the Egyptian gods had become entirely Roman.[[30]]
The climax of their power seems to have been reached at the beginning of the third century; later on the popular vogue and official support went to other divinities, like the Syrian Baals and the Persian
Mithras. The progress of Christianity also deprived them of their power, which was, however, still considerable until the end of the ancient world. The Isis processions that marched the streets of Rome were described by an eye witness as late as the year 394,[[31]] but in 391 the patriarch Theophilus had consigned the Serapeum of Alexandria to the flames, having himself struck the first blow with an ax against the colossal statue of the god that had so long been the object of a superstitious veneration. Thus the prelate destroyed the "very head of idolatry," as Rufinus put it.[[32]]
As a matter of fact, idolatry received its death blow. The worship of the gods of the Ptolemies died out completely between the reigns of Theodosius and Justinian,[[33]] and in accordance with the sad prophecy of Hermes Trismegistus[[34]] Egypt, Egypt herself, lost her divinities and became a land of the dead. Of her religions nothing remained but fables that were no longer believed, and the only thing that reminded the barbarians who came to inhabit the country of its former piety, were words engraved on stone.