Theodosius II. By Marie-Lan Nguyen (User:Jastrow), 2009, CC BY 2.5, https://commons.wikimedia.org/w/index.php?curid=7488727

Justinian I, emperor of the Eastern Roman Empire, 527–65 C.E., was a zealous persecutor of all non-Christians in the Byzantine Empire. He confirmed and extended the anti-Jewish laws of Theodosius II, determining the legal status of Jews in the Byzantine Empire for the next seven hundred years. These laws intended to prohibit the Jewish marriage ceremony itself and all laws pertaining to marriage, and abrogate the Jewish legislation regarding the legal age of marriage and degrees of permitted kinship. Codex Justinianus restricted not only Jewish religious life, but also the civil rights of Jews as citizens in a Christian society.

The same three Augusti to Infantius, Comes of the East:
7. None of the Jews shall keep his custom in marriage unions, neither shall he contract nuptials according to his law, or enter into several matrimonies at the same time.⁹⁰

Given on the Third Day Before the calends of January at Constantinople, in the Consulate of Theodosius Augustus for the third time and Abundantius [30 December 393].

5:21 The same Augustus to Johannes, Pretorian Prefect:
Since many judges in course of determining litigation addressed us needing our oracle in order that it will be revealed to them what must be decided about heretic witnesses, whether their testimonies should be accepted or rejected, we determine that there should be no participation of a heretic, or even of those who practice the Jewish superstition, in testimonies against Orthodox litigants, whether one party to the trial is Orthodox or the other. We grant, however, to the heretics and to the Jews, that whenever they shall deem fit to have litigation among themselves they shall have mixed agreement and even witnesses worthy of the litigants. . . . On the other hand, we allow their testamentary testimonies and those found in last wills or in contracts without any discrimination, because of the benefit of this necessary usage, lest the means of demonstration be reduced.
Given on the fifth day before the calends of August at Constantinople, after the consulate of the illustrious Lampadius and Orestes [28 July 531].

89. Trans. A. Linder, The Jews in Roman Imperial Legislation (Detroit: Wayne State University Press; Jerusalem: Israel Academy of Sciences and Humanities, 1987), pp. 193, 373–4.

90. Prohibiting polygamy, which was still permissible according to Jewish law.