During this period the simple manners and the honesty which had obtained among the Jews of Babylonia in former times, fell to a low ebb with many of them, and made room for luxury, vanity, and thirst for power. Many a teacher of the Law was clad in gorgeous garments and was carried about in a gilded litter. They no longer felt themselves one with the people from whom they had risen, but constituted a particular caste, a patrician class, who mutually protected and maintained one another's interests, looking down with pride and contempt on the lower orders of the populace. Raba himself admitted that whenever he was called upon to decide a point of law in which a person of the same class of society as himself was concerned, he was unable to sleep until he succeeded in interpreting the law in his favor. If a member of the school brought his produce to market, he was invested with the privilege of being allowed to sell before any one else, in order that he might obtain higher prices. The cause of a member was always heard first in the court. The teachers of the Law of such communities as paid their taxes in a lump sum, were exempt from all imposts. Raba allowed the associates, in places where they were not known, to declare their rank, in order that they might enjoy the advantages attaching thereto. What a contrast to former times, when the Tanaites hesitated, at the risk of their lives even, to derive any benefit from their knowledge of the Law! Raba went to extreme lengths in according privileges to the doctors of the Law. He permitted the associates to pass themselves off as worshipers of fire in order to escape payment of the charag.

The course of conduct thus pursued by the learned classes gradually awoke a dislike of them among the people. The lower classes spoke of them contemptuously as "those scholars." The mockery expressed by this epithet must have been so bitter that on their side the teachers of the Law branded as heretics (Epicureans) all who made use of the expression. Scholarship thus no longer obtained recognition. "What do we profit by the scholars?" the people asked themselves; "all their knowledge is employed for their own benefit." At the head of this opposition to the Rabbis stood the family of the physician, Benjamin of Machuza, which seems to have been possessed of great importance, as Raba paid great attention to its members. "What advantage do we really derive from the teachers of the Law?" said they jeeringly; "they can neither allow us to eat ravens, nor forbid us to eat pigeons?"—meaning that in spite of all their dialectics they were unable to proceed beyond the circle of established customs. Although Raba declared this utterance of Benjamin Assia to be heretical, it does not appear that he excommunicated him, but rather that he treated him with great consideration; it is probable that the latter belonged to the retinue of the Prince of the Captivity.

Meanwhile the zeal for the study of the Law had greatly increased. Disciples crowded in even greater numbers than formerly to Raba's academy in Machuza, neglecting in their ardor their business pursuits. Raba was obliged to warn them against this excess: "I pray you do not come to my school in the spring and autumn months, lest you should neglect the time of the harvest and of the preparation of wine and oil, and so be troubled throughout the year by the cares of life." Raba's discourses were even more popular than Abayi's by reason of the clearness of his explanations, the exactitude of his distinctions, and the boldness of his treatment of the subject-matter of tradition. Raba showed a decided preference for analyzing the Mishna to the bare study of its dry subject-matter. The former method offered a wide field for the employment of dialectical powers, while the Mishna, taken in its simplest sense, became a mere matter of memory. On this account Raba placed the Amoraïm above the Tanaites; the former explained, or explained better, such points as were doubtful to the latter. He was accustomed to say that a grain of pepper (acuteness) was better than a basketful of melons. In contrast to Zeïra I, who was adverse to that method of teaching which encouraged ingenious reasoning, and valued highly the simplicity of the Mishna, Raba declared that "whoso breaketh stones injureth himself thereby (Eccles. x. 9); thus are they characterized who know merely the Mishna; but he who splitteth wood warmeth himself; such are they who are acquainted with the Talmud." The true Talmud, the attractive collection of nice questions, answers, comparisons and distinctions, the lofty flight of thought, which, starting from a point, passes with the quickness of lightning over the intermediate steps of a chain of reasoning, the dialectic form of the Talmud is the product of this period. The triumvirate, Rabba, Abayi, and Raba, were Talmudists in the real meaning of the word, i. e., dialecticians. In this sense the Talmud was the creation of the Pumbedithan and Machuzan schools. In Judæa there was scarcely a notion of it. By reason of his extensive acquirements, his profound intellect, and perhaps also on account of his wealth, Raba remained the sole authority during his continuance at the head of the academy. Questions were referred to him even from Judæa, when the frequent persecutions under Constantius and Gallus involved the Holy Land in the deepest misery.

This period was by no means the happiest for the Jewish subjects of the Persian crown; they were not spared during the obstinate struggle between Rome and Persia. A Persian army was stationed at Machuza, and had to be maintained by the inhabitants of the town. As the population was entirely Jewish, this duty was attended with many inconveniences. Shabur II was no friend of the Jews. In ancient times numerous Jewish families had been transported to Armenia, and now lived there in their own cities; of these, Shabur led an immense multitude (estimated at 71,000) into captivity, and colonized them in Susiana and Ispahan. This latter city, which had formerly been the capital of the Persian empire, received the name of Jehudia, from the many Jews who settled there after the captivity. Shabur appears to have oppressed the Jews of Babylonia in no less degree, for Raba was obliged to expend considerable sums of money in preventing persecution. His friends extolled his good luck in being, to a certain extent, exempted from the misfortunes to which the Jewish people had been predestined, seeing that up till then he had been subjected to no extortions. To these congratulations Raba replied as follows: "You know not how much I am obliged to do in secret for Shabur's court!" On one occasion it was with great difficulty that he managed to escape a personal danger which threatened him in his capacity of principal of the schools. He had ordered a Jew to be flogged for having held carnal intercourse with a Persian woman, and the chastisement had caused the death of the culprit. The case happening to come to Shabur's knowledge, he commanded a heavy punishment to be inflicted on Raba for having exercised the criminal jurisdiction. The latter appears to have escaped the penalty by flight, but his house was pillaged. All further consequences of this occurrence were averted by Ifra, the queen-mother, who is reported to have said to her son: "Do not meddle in any way with the Jews, for God grants them whatever they pray for." In striking contrast with her son, Ifra-Ormuzd entertained a special liking for the Jews, and in particular for the teachers of the Law, to whom at times she vouchsafed a glance into the most secret recesses of her heart. In the same way as she had formerly sent a purse of gold to Joseph, she now forwarded 400 golden denars to Raba. Rami, a contemporary, was of opinion that this present ought to be refused, as it was not lawful to receive alms of the heathens. Notwithstanding this, Raba accepted the money, but distributed it amongst the heathen poor. The queen-mother Ifra also sent an animal for sacrifice to the principal of the school in Machuza, which she requested might be offered up according to the Jewish rites, in order to prove her adoration of the only God. Raba did not live to see either the introduction of the calendar by Hillel, or the short period during which prosperity smiled upon the Jews. He died after holding his office for fourteen years.

After Raba's death the importance of Machuza began to decline, and Pumbeditha, which had unwillingly surrendered the palm to Raba, now occupied its former position. It is remarkable that from this time forward mediocrity began to reign, as if intellectual activity needed recreation after so many exertions. Not one of Raba's successors was sufficiently able to compensate for his loss. The principals of the Babylonian schools, Nachman ben Isaac, Papa, and Chama of Nahardea, were possessed of no conspicuous importance; the Pumbedithan spirit of severe analysis and ingenious dialectics was indeed cultivated, but in nowise advanced.

Nachman ben Isaac (born about 280, died 356) was chosen as the leader of the Pumbedithan Metibta, but merely on account of his advanced age, his extraordinary piety, and perhaps also of his independence. His tenure of office only extended over four years, and was not rendered memorable by any noteworthy feature. During this period a new academy was founded at Nares, in proximity to Sora, situated on the canal of the same name.

The founder of this new academy, of which he became the principal, was Papa bar Chanan (born about 300, died 375). He had early been left an orphan, was wealthy, and by trade a brewer of beer from dates. His friend, Huna ben Joshua, equally wealthy, and his partner in business, became a teacher at this academy. But the two together were not able to fill the void which Raba's death had occasioned. It is true that the members of the Machuzan academy gathered around them; but opportunities soon arose of effecting comparisons, the results of which were anything but favorable to the new chiefs.

The following anecdote will serve to indicate the character of the principal of the Nares academy. Certain of the younger teachers of the Law had come to Nares in order to be present at Papa's lectures. This latter, however, left his subject in so confused a condition, that they secretly began to make signs one to the other. Papa, seeing this, was exceedingly mortified, and said to them: "Let those present depart from here in peace." Another member, one Simaï bar Ashi (father of the Ashi who became famous later on), used to importune Papa with questions which quite exceeded his modest capabilities. Papa, in despair lest he should be put to shame before his pupils, would throw himself down in prayer, and beseech the merciful God to preserve him from the terrible feeling of confusion. Simaï, having been an unobserved witness of this fervent prayer, made up his mind that henceforward he would keep silence, and no longer involuntarily mortify Papa.

In the Halacha, Papa was the representative of a school which was so devoid of self-dependence, that its partisans did not even hold an opinion of their own concerning the views of others. Whenever two or more conflicting opinions left the meaning of a precept of the Law in doubt, Papa would say: "Let us adopt both views, or act according to all these opinions." Papa remained at his post during nineteen years (355–375), and the stupor into which all minds were thrown during this period was only dissipated by his successor. Pumbeditha possessed a principal of equal insignificance in Chama of Nahardea, whose character a single anecdote will suffice to indicate. King Shabur asked him whether the practice of burying the dead was founded on the Torah, or whether it was simply an ancient custom. The question arose from the usage of the Persians, who neither buried nor burned the corpses of their dead. Chama, however, could bring forward no passage of Scripture in support of burial. Acha ben Jacob, a member of the household of the Prince of the Captivity, and therefore privileged to say many things, expressed the following opinion of this principal: "The world is delivered into the hands of fools; why did he not instance the verse, 'And thou shalt bury him on the same day'?"

In the course of the twenty-one years (356–377) during which Chama held office, a change occurred in the Roman Empire which was not without weighty consequences for the communities of Judæa and Babylonia. A nephew of the Emperor Constantius, Julian, effected a revolution which, however, was only temporary. Emperor Julian was one of those masterful characters who impress their names indelibly on the memory of man. It was only an early death and the hatred of the ruling Church which prevented him from obtaining the title of "Great." Although a member of Constantine's family, the fratricidal sword of the Constantines hung over his head, and he was compelled by fear of death to give hypocritical adhesion to the Christian religion, which he hated. Almost by a miracle he was created co-emperor by his uncle Constantius, who hated him from the bottom of his heart, and had already held a council about his death. A military revolt in his favor, and the unexpected death of his enemy Constantius, put Julian in possession of exclusive power. Known in the history of the Church as the Apostate (Apostata, Parabata), Julian made it the duty of his life to realize the ideal, which association with his teachers, Libanius and Maximus, had suggested to him, and which had been further ennobled by his rich mind. His favorite thoughts were to protect the oppressed of all nations and religions, to promote the well-being of all his subjects, more especially by alleviating the burden of taxes, to revive the philosophical sciences, which had been condemned by the Christian emperors, to restore the ancient religion, freed, however, from its most conspicuous blemishes, which had rendered it so contemptible and ridiculous; finally, to confine Christianity, which had gained so much power during so short a period, within its proper limits. Mindful, however, of the persecution to which he himself had been subjected, he refrained from retaliating on the Christians, in spite of their mania for persecution. Still, he was desirous of restraining their encroachments, and therefore deprived them of their influence in civil and scientific matters, and attempted to lower them in the appreciation of the learned classes by the employment of the weapons of the intellect and delicate satire. He called Jesus a Galilæan whom credulity had exalted to a god, and spoke of the Christians by the nickname of Galilæans. For this reason he was all the more friendly toward the Jews, and was the only emperor after Alexander Severus who evinced serious interest in Judaism. He was led by more reasons than one to prefer Judaism. Brought up in the Christian religion, he had become acquainted with Judaism through the Holy Bible, and the more Judaism was hated and persecuted by Christianity, the greater was the reverence with which he regarded it. The emperor even admitted that he had been greatly shocked by the cruel oppression to which the Jews were exposed during the reign of Constantius, when their religion was branded as blasphemous by victorious Christianity. Julian was greatly impressed by the God of Judaism, as described in Holy Writ, and acknowledged him as the "Great God." He refused to believe, however, that beside Him there existed no other gods. He especially admired the benevolence of the Jews, and was astonished that they cared for their poor with such zeal that no beggars existed among them. He was also desirous of deeply mortifying the Christians by the preference which he exhibited for the Jews, for the former were at great pains to prove the superiority of their religion by the abasement of the latter. He entertained a particular predilection for the sacrificial cult, and for this reason he was especially pleased with the Jewish system of sacrifices, with the solemn pomp of the Temple and the priests. The emperor reproached the Christians with having rejected the God and the worship of Judaism, but he particularly blamed them for having discarded the sacrificial service. It was true that the Jews did not then offer sacrifices, but this was only because they no longer possessed a Temple. Finally, the idea may have occurred to Julian to dispose the Babylonian Jews in his favor for the Persian war which now occupied his whole attention. He desired, if not to obtain their active support, at least to prevent them from offering fanatical resistance.