[Iustiniani Institutiones]

a See Digest part of the Corpus Juris Civilis on the rites of marriage, law 1, where Accursius Florentinus notes this is not well known.
b Of parents. That is, those who are of their own right, whatever their age may be, and so for the mother. But children in potestate under the power of the father, whatever their age, are as in Digest on those who are of their own right, law "namely of citizens."
c In potestate. Therefore, concerning those emancipated, see the same, as in Code on this, law 1, "widows." If that is the son, it is not a precept that he cannot be emancipated, he is said to be a son. See Digest on the contrary, law 1, par. "if emancipated" and Digest on the rites of marriage, law "son emancipated," Accursius.
e And civil. Because it is in potestate by reason of civil law, as above, title 1, par. "law."
f And natural. Because it is possible, as in Digest on justice and law, law 2.
g Ought. Otherwise as above, see Digest on the status of men, law "Paulus," 1, par. "see." But he does not explicitly order it to be done, as in Digest on betrothals, law "in betrothals," at the end.
h Whence. Because the father's consent must be asked.
i He may. Since he is present, he can consent, as in Digest on those who are in power, law 2, par. "madman."
k Concerning the son. For regarding the daughter, consent was easy, perhaps because there is warmer blood in her, as in Authenticum on those not to be chosen, par. "with," col. 1, or rather because of the fragility of the sex, as in law 1, in the beginning, so the first does not please.
l Decision. That is, judgment or law, as in Code on this, end, "of the madman."
m Your decision.
n Of the madman. And so if he was captured and was absent for three years, or if it is not known whether he lives or not, as in Digest on this, law "nephew," par. end, and "he so."
o According to the given. That is, with the authority of the guardian of the father and a dowry according to the size of the father's estate, as in Code on this, law "of the madman," at the end. But by canon law, the consent of those whose marriage is at issue is sufficient, but that perhaps holds for others, not for children.

An image of the initial 'I' in red with decorative flourishes, typical of early printed legal manuscripts.

are joined in the degree of kinship. There is a certain similar observance but not as great. For instance, between a brother and sister, marriage is prohibited, whether they were born from the same father and same mother, or from one of them. But if a sister begins to be yours through adoption, as long as the adoption exists, marriage cannot consist between you and her. But when the adoption has been dissolved through emancipation, you can take her as a wife.

But even if you have been emancipated, there is no impediment to the marriage, and therefore it is established that if anyone wishes to adopt a son-in-law, he ought to emancipate him before his daughter. And if anyone wishes to adopt a daughter-in-law, he ought to emancipate his son before.

One cannot take the daughter of a brother or sister as a wife. But neither can one take the granddaughter of a brother or sister, because they are in the fourth degree. For whose daughter one cannot take as a wife,

Otherwise, degrees are taken according to the canons than according to us, as you will say, on degrees.
f Hear, thus, Digest on verbal obligations, "if I stipulate."
f This, Digest on children and power, "who asks," at the end.
g Dissolved. Because she is emancipated, so that it differs from the following case.
h Son-in-law. That is, the husband of the daughter.
f Daughters. Because by making an emancipation, she ceases to be an agnata kin through the male line. Therefore, she could not be made an agnata by such an adoption, as in Digest on adoption, law 1. Today, however, she does not cease, as said on the law of agnation. And thus, today, it does not hold.
d Daughter-in-law. That is, the wife of the son, as is proven on this, par. "of affinity."
g Brother. Whose daughter or grandmother I cannot take. But I can take the granddaughter, who is my cousin, as said on this, par. "of the two." I reply that this rule is strictly understood in the case in which it speaks, and in every similar one, when I and he cannot take the daughter, we are in the second degree to the stem, and in the power of the same. And so when I can take the daughter of a brother or sister. This holds for natural kin, otherwise for adoptive ones, as said previously, Accursius Florentinus.
h Of him. Thus construe: you do not seem to be impeded from taking a wife.
i Civil law. Concerning natural it is established; concerning civil, I prove it thus: that daughter of an adoptive sister is not in the power of the mother, as said on the meaning of words and definitions, par. "what of the cause." Because she is not in the power of the son who adopts the mother, for the mother is not in his power, because they are with others who are in the power, as said in title 1, par. "that." And Digest on adoption, "father." But that mother herself adopted is joined to me by agnation through the father, in whose power she is, Digest on adoption, law "which adopted."
k Of the two. Or according to law, as above, and Code on this, "to be celebrated." Otherwise by canon law. Or say this paragraph speaks of adoptive ones; otherwise for natural ones.
l Also aunt. Which is the sister of the father.
n Also maternal aunt. Not carefully, because it does not repeat the adoptive maternal aunt, because a maternal aunt or uncle is not made by adoption, as above and earlier, on this, par. "of him." And Digest on this, "finally." Otherwise, law "adoption," par. "above." It seems, Digest on the rites of marriage, law "through adoption," at the end. I reply: No. That is understood when there is adoption into a grandson as if born from a daughter, or into a great-grandson born from a grandson born of a daughter, which I can do just as if I had no son, as said in title 1, par. "it is permitted." For then the sister and brother of him in whose place the adoption is made, is the maternal aunt and...

neither is her granddaughter permitted. But you do not seem to be impeded from taking as a wife the daughter of the woman whom your father adopted, because she is joined to you by neither natural nor civil law.

However, the children of two brothers or sisters, or of a brother and sister, can be joined. Also, it is not permitted to take an aunt, even an adoptive one, as a wife, nor a maternal aunt, because they are held in the place of parents. For which reason it is true that a great-aunt and a great-maternal aunt are also prohibited from being taken as wives.

One must abstain from marriages also due to the veneration of affinitas affinity/relationship by marriage. For example, it is not permitted to take a stepdaughter or daughter-in-law as a wife, because both are in the place of daughters. This, of course, is to be understood if she is your daughter-in-law or stepdaughter. For if she is still your daughter-in-law, that is, if she is still married to your son, you cannot take her as a wife for another reason, because

p Therefore, because marriages are made according to the precepts of the laws, therefore...
q Not all. That is, women.
r Four. That is, women.
s Among them to infinity. So that if Adam were alive today, he could not have a wife, according to Jo, as in Digest on the rites of marriage, law "none."
u Among. Not as much, that is, up to the 8th degree according to the canons, as in Extra, q, law 2, chapter "progeny," and chapter "of consanguinity," and chapter "in the coupling," and chapter "to none," par. "according to," law "up to the fourth," as said on this, par. "of the brother." The same holds today by canon law, as in Extra on consanguinity and affinity, chapter final, if however.

the same woman cannot be married to two men.