Did Roman Law Actually Prohibit the Building of New Synagogues?

5th c. CE · Codex Theodosianus 16.8.27 (+ related), 423 CE

What the ancient record says

Yes, by the 5th century restrictions once mainly in sermons and canons entered imperial law. A 423 CE law addresses synagogues directly, distinguishing existing from new: existing synagogues were not authorized for indiscriminate destruction, but construction of new ones was prohibited.

Inaccurate to write "Rome ordered every synagogue destroyed in 423", existing synagogues received some legal protection against unlawful seizure/destruction while new construction was forbidden (protection and restriction in the same system). In practice a community might keep a standing synagogue but, as populations changed/expanded, could not lawfully build more, a structural disadvantage without ordering immediate destruction.

Legal inequality need not look like "destroy everything today"; it can operate through building, property, office, conversion restrictions and limits on institutional growth. No evidence establishes perfectly uniform enforcement empire-wide (law vs local enforcement differ); the law proves the restriction existed.