Shmuel bar Abba, known simply as Shmuel, ran the great academy at Nehardea on the Euphrates in the first half of the third century CE. He was a physician, an astronomer precise enough that the Talmud credits him with the calendar reckoning "Shmuel's paths through the sky," and one of the founding giants of Babylonian rabbinic scholarship. His legal opinions fill hundreds of pages of the Talmud. Yet the sentence for which the world remembers him most is only four words in Aramaic: dina d'malkhuta dina - the law of the kingdom is law.
The phrase sounds modest. What it did was remarkable. It gave Jews under Sassanid Persian rule, and later under every succession of empires and kingdoms, a principled reason to obey civil law without treating that obedience as a religious capitulation. Tax obligations, commercial contracts, land tenure, property transfers - wherever state law governed these honestly and uniformly, a Jew was not merely permitted to comply but was halachically required to do so. The Torah's own authority stood behind the instruction: not because the foreign king deserved deference, but because a stable civil order was a condition for life, and life was sacred. Shmuel located the principle inside Jewish law rather than outside it. That was the move.
The record
The formula dina d'malkhuta dina appears four times in the Babylonian Talmud - in tractates Nedarim 28a, Gittin 10b, Bava Kamma 113a-b, and Bava Batra 54b-55a. Each instance applies it to a concrete legal scenario: tax avoidance, the validity of documents drawn under non-Jewish jurisdiction, the status of land seized by a king and sold on. In every case the ruling is attributed to Shmuel, the head of the Nehardea academy who died around 254 CE. The Babylonian Talmud was redacted in its near-final form by the Savoraim around 500-600 CE, but the attribution to Shmuel is consistent across all four occurrences and is accepted by medieval and modern scholarship alike. (Babylonian Talmud, standard Vilna edition; see also Saul Lieberman, Greek in Jewish Palestine, 1942, on the Hellenistic legal background.)
Shmuel was working in a particular world. Nehardea sat inside the Sassanid Persian Empire, which had replaced the Parthians in 224 CE. The Sassanids were not uniformly hostile to Jews - the Jewish exilarchate, the officially recognised communal leadership in Babylonia, functioned under their patronage - but they were a sovereign power with their own courts, their own land law, and their own tax system. Shmuel's relationship with King Shapur I is described in the Talmud as collegial; the two men are said to have met and debated. Whether or not those stories are historically exact, they reflect something real: Shmuel operated at the frontier between Jewish autonomy and Persian sovereignty, and he thought carefully about where the lines ran. Dina d'malkhuta dina was not a concession wrenched out of weakness. It was a principled articulation of how a community with its own law could inhabit a state with its own law, each recognising the other's domain.
The record
Shmuel's standing as an astronomer is confirmed by the Talmud's own astronomical discussions, particularly in tractate Rosh Hashanah 20b and Berakhot 58b, where calculations attributed to him concerning the solar year and planetary cycles are recorded. His approximation of the tropical year - 365 days, 6 hours - was used as the basis of the "Shmuel cycle" for calendar reckoning, and was still cited by Maimonides in the twelfth century (Mishneh Torah, Laws of the Sanctification of the Month, ch. 9-10). The dual expertise - astronomy and civil law - was not unusual for the Babylonian academies, where the interface between Jewish and Persian intellectual culture was a productive space. Nehardea itself was destroyed in a raid by the Palmyrene general Odenathus around 259 CE, a few years after Shmuel's death; the academy relocated to Pumbedita, where it continued as one of the two great Babylonian centres of learning for several more centuries.
The afterlife of dina d'malkhuta dina is a story of extraordinary reach. Medieval halakhic authorities debated its precise scope: did it cover only fiscal matters, or extend to personal status? Did it apply only in diaspora or also in the Land of Israel? Rabbenu Gershom, Rashi, Maimonides, and Nachmanides all engaged with Shmuel's ruling across the following nine centuries, each applying it to the conditions of their own communities in Rhineland, Egypt, or Catalonia. The principle arrived in the modern era intact enough to inform responsa literature on topics Shmuel could not have imagined - copyright, banking regulation, traffic law. A single Aramaic sentence coined in third-century Babylonia kept offering answers because the underlying question - how does a people with its own sovereign law live honestly under someone else's? - never went away.
What Shmuel gave the tribe was not a compromise. It was a framework - one that took diaspora seriously as a condition to be navigated with intelligence rather than endured with resentment. He did not tell Jews to forget their own law. He told them that honouring a just civil order was already inside their own law, properly understood. That confidence, the confidence of a tradition strong enough to engage the world on the world's terms, runs through the best of Jewish intellectual history. Shmuel demonstrated it in four words. The academies of Babylonia, and every community that drew on their legacy, carried those words forward.
