• Age: If either party is under the required age, the marriage is invalid. This is an ecclesiastical impediment, and so does not apply to a marriage between two non-Catholics. However, in a marriage between a Catholic and a non-Catholic, the age limitation also applies to the non-Catholic party.
• Impotence: To invalidate a marriage, the impotence must be perpetual [i.e., incurable] and antecedent to the marriage. The impotence can either be absolute [i.e. with regard to any person of the opposite sex] or relative [i.e. with regard to the specific person of the spouse]. 
• Previous Marriage [also known as the impediment of the "ligamen", referring to the bond of the previous marriage]: Whether conducted in the Catholic Church, in another Church or Ecclesial Community, or solely in terms of Civil Law, any previous marriages by either party wishing to marry [again] must be declared null before a wedding can take place in the Catholic Church. This is irrespective of the religion of the party previously married. If a prior marriage cannot be declared null, no new marriage is possible.
• Disparity of Cult: A marriage between a Catholic and a non-baptised person is invalid unless a dispensation is granted by the local Ordinary [usually the Bishop].
• Holy Orders: One of the parties has received sacred orders [Deacon, Priest or Bishop]. This impediment is of ecclesiastical law and may only dispensed by the Apostolic See [Rome].
• Perpetual vow of chastity: One of the parties has made a public perpetual vow of chastity as a monk or religious sister or in some other form of consecrated life. This impediment is of ecclesiastical law and may only dispensed by the Apostolic See.
• Abduction: One of the parties has been abducted for the purpose of contracting marriage.
• Crime: One or both of the parties has brought about the death of a spouse for the purpose of entering marriage with each other. This impediment is of ecclesiastical law and may only dispensed by the Apostolic See.
• Consanguinity: The parties to the marriage are close blood relatives. The relationship between, for example, a father and daughter, or grandparent and grandchild, is known as the "direct line" of consanguinity. Marriage is always prohibited in the direct line. The relationship between first cousins would be known as the "collateral line" of consanguinity. Marriage is prohibited up to and including the "fourth degree" on the collateral line. Degrees are calculated easily, by counting the number of persons between one relative and another, and including both relatives. For example, a first cousin is the fourth degree [e.g., a woman, her father, her father’s sister and that sister’s son]. An aunt is the third degree [the person, the mother, the mother’s sister]. A second cousin would be the fifth degree, and so marriage to a second cousin would not be prohibited whilst marriage to an aunt or first cousin would be invalid.
• Affinity: This refers to the direct line whereby the two persons are not related by blood, but are legally related as the result of a valid marriage. For example, a woman may not marry her step-father or her mother’s step-father. There is no impediment of affinity in the collateral line.
• Public propriety: Whilst affinity is calculated on the basis of a valid marriage situation, the impediment of public propriety is based on cohabitation. If it is publicly, or "notoriously", known that two people live together, marriage is prohibited only in the direct line and only in the first degree. For example, a man may not marry the daughter of his female partner born to her from a previous liaison [whether marriage or not].
• Adoption: Those who are legally related by reason of adoption cannot validly marry each other if their relationship is in the direct line or in the second degree of the collateral line. For example, if a married man and wife adopt a daughter, the man may not marry his adopted daughter’s sister nor, of course, his adopted daughter [e.g. if his marriage were declared null, he could not then marry the adopted daughter].

The documentary procedure is used to process marriage nullity petitions which allege the presence of a "an impediment to marriage". 

Documentary cases are also judicial cases, that is, decided by a judge, but without his having to follow the more solemn procedure proper to deficiency of consent cases. Due, in fact, to the existence of one or more documents which prove the presence of a "diriment impediment"  at the time of consent, the law prescribes a shorter process. The condition is that the document(s) in question is(are) not subject to any contradiction or objection, and that there is certainty that no dispensation from the impediment  was given.