In this episode, we follow the parting of rabbinic Judaism and Christianity into the fourth and fifth centuries, when Christianity becomes entangled with imperial power and the separation begins to take on legal and administrative form. The key thread is simple: overlap does not vanish on its own. It has to be discouraged, stigmatised, and eventually priced out.

We begin in Antioch with John Chrysostom, whose sermons are aimed at Christians still attending Jewish festivals and spending time in synagogues. His panic is evidence that ordinary mixing remained normal enough to worry bishops well into the late fourth century. From there we move to the politics of time: Nicaea, Easter, and the drive to make Christian sacred rhythm independent of Passover, reinforced by rules like Laodicea’s ban on ‘judaizing’ through Sabbath rest. We then trace the “ratchet” by which argument becomes canon and canon becomes law: the Edict of Thessalonica makes orthodoxy an official category, and the Theodosian Code turns boundary-making into enforceable policy. The Callinicum episode shows the new leverage bishops could claim against imperial restitution for Jews. Augustine’s “toleration” appears as a theology of managed Jewish survival, and Jerome’s translation work exposes the ongoing Christian dependence on Jewish language knowledge. We end in the Jewish east, where rabbinic authority consolidates through portable scholarship and the Babylonian Talmud, and with the episode’s closing claim: the split was enforced through calendars and law, yet the shared library never stopped binding the rivals together.

• Overlap is still active: Chrysostom’s Antioch and the need for boundary policing
• Sacred time as identity: Easter, Passover, and the push for calendar independence
• Sabbath and Sunday: Laodicea’s anti-‘judaizing’ rule as social engineering
• The ratchet: preaching → canons → law
• Orthodoxy becomes state-backed: Edict of Thessalonica (380 CE)
• Law as administration: Theodosian Code (438 CE) and the legal handling of Jewish life
• Callinicum (388 CE): synagogue burning, restitution, and Ambrose’s intervention
• Augustine: Jews preserved as “witness”, survival without standing
• Jerome: Hebrew, the Vulgate, and the anxiety of dependence
• The Jewish east: academies, portability, and the Babylonian Talmud as a “library of argument”
• From neighbour to symbol: how rhetoric replaces relationship when Jews are absent
• The shared library: why ‘judaizing’ remains a durable fear-category even after separation

• John Chrysostom (Antioch, 386–387 CE)
• Council of Nicaea (325 CE) and Constantine’s post-Nicene letter in Eusebius, Vita Constantini
• Council of Laodicea (Canon 29)
• Edict of Thessalonica (380 CE)
• Theodosian Code (published 438 CE)
• Callinicum synagogue burning (388 CE), Ambrose of Milan’s letter to Theodosius
• Augustine of Hippo, Against Faustus (Cain as figure for Jewish preservation)
• Jerome, Hebrew scholarship, and the Vulgate
• Palestinian patriarchate abolished (425 CE), shift of Jewish scholarly gravity eastward
• Sura and Pumbedita; Babylonian Talmud (5th–6th centuries)

The separation was never a single event. It became real through calendars, rules, and law, and through a shift from lived neighbourliness to inherited rhetoric. Yet Christianity could not fully escape Judaism’s texts, and Judaism survived partly by building authority that could travel.

Read the written version: https://open.substack.com/pub/danjacobslondon/p/parting-ways-55-the-emergence-of?r=oc9m&utm_campaign=post&utm_medium=web&showWelcomeOnShare=true