Given in response to complaints presented by Jews, [this law] recognized the exclusive right of the Jewish authorities in Palestine and in the Diaspora, headed by the patriarch, to excommunicate and to revoke excommunications. The imperial authorities are denied any right in this matter. Although the specific case referred to is unknown to us, the legislation it triggered was of great importance, for it enunciated a clear and comprehensive recognition of the organizational and legal autonomy of the Jews throughout the Empire, under the rule of the patriarchs, in all matters related to their religion.
From Amnon Linder, The Jews in Roman Imperial Legislation, p. 186.
Note: The institution of the Jewish patriarch was abolished c. 425.