In the Catholic Church, a declaration of nullity, commonly called an annulment and less commonly a decree of nullity, and in some cases, a Catholic divorce, is an ecclesiastical tribunal determination and judgment that a marriage was invalidly contracted or, less frequently, a judgment that ordination was invalidly conferred.

A matrimonial nullity trial, governed by canon law, is a judicial process whereby a canonical tribunal determines whether the marriage was void at its inception (). A "Declaration of Nullity" is not the dissolution of an existing marriage (as is a dispensation from a marriage ratum sed non consummatum and an "annulment" in civil law), but rather a determination that consent was never validly exchanged due to a failure to meet the requirements to enter validly into matrimony and thus a marriage never existed.

The Catholic Church teaches that, in a true marriage, one man and one woman become "one flesh" before the eyes of God. Various impediments can render a person unable to validly contract a marriage. Besides impediments, marriage consent can be rendered null due to invalidating factors such as simulation or deceit, or due to psychological incapacity.

In 2015, the process for declaring matrimonial nullity was amended by the matrimonial nullity trial reforms of Pope Francis, the broadest reforms to matrimonial nullity law in 300 years.Pope Francis announces biggest changes to annulment process in centuries, The Washington Post, accessed 8 September 2015 Prior to the reforms, a declaration of nullity could only be effective if it had been so declared by two tribunals at different levels of jurisdiction. If the lower courts (First and Second Instance) were not in agreement, the case went automatically to the Roman Rota for final decision.

Reasons for nullity Certain conditions are necessary for the marriage contract to be valid in canon law. According to and , the Church cannot separate what has been united by God, but with his aid can rule that a marriage has been null since the time of its celebration. The lack of any of these conditions makes a marriage invalid and constitutes legal grounds for a declaration of nullity. Accordingly, apart from the question of diriment impediments dealt with below, there is a fourfold classification of contractual defects: defect of form, defect of contract, defect of willingness, defect of capacity. For a declaration of nullity, proof is required of the existence of one of these defects, since canon law presumes all marriages are valid until proven otherwise.Code of Canon Law, Canon 1060 . Defect of canonical form Members of the Catholic Church are required by  1108 to marry in canonical form. That means that the marriage of a Catholic is valid only if it is contracted before the local ordinary (e.g. the bishop), the parish priest or a cleric deputed by either of them and two other witnesses are present. The cleric is not the minister of the sacrament; the husband and wife are the ministers by exchanging vows, though the cleric presides over the exchange of the vows and any mass or nuptial liturgical celebration. If one of the parties is Catholic, but there is a serious reason why the marriage should be celebrated in a civil ceremony or in front of a non-Catholic minister, a dispensation can be granted according to  1127 § 2. If no dispensation was granted in advance and the couple – one of them being a Catholic at the time of the wedding – did not observe the canonical form, the marriage is considered invalid in the eyes of the church.

Because "[m]arriage possesses the favor of law" according to  1060, a declaration of nullity by the proper ecclesiastical authority is necessary to prove that the marriage was indeed invalid due to a defect of form. This is the case, e.g., when a couple marries before a priest who did not have the proper authority to witness weddings, or before an insufficient number of witnesses.

However, in situations where there was a complete absence of the canonical form (e.g. if the marriage was concluded in a civil ceremony) and a Catholic later wants to get married in canonical form to a different person, no formal judicial process is required beyond the prenuptial investigation mandated by can. 1066–1067. However, in may dioceses, particular law requires these "lack of form" cases to be handled at the tribunal instead.

If a couple which was married without adherence to the proper canonical form later wants to rectify the lack of form and be married validly in the eyes of the church, the marriage can be regularized by being contracted again in canonical form.

Impediments

If one of the parties were prohibited from marrying by a diriment impediment (from the Latin for "interrupting"), the marriage is invalid. Because these impediments may not be known at all, the marriage is called a putative marriage if at least one of the parties married in good faith.

Diriment impediments include: One or both parties is below the absolute minimum age of 16 for males and 14 for females Antecedent and perpetual impotence (not to be confused with sterility) Ligamen, or being already validly married1983 Code of Canon Law, Can. 1085 The situation in which one party is a Catholic and the other has not been baptized (unless a dispensation is granted) The man was ordained to holy orders Either party made a public perpetual vow of chastity in a religious institute Abduction with the intent of marriage (known as raptus), is an impediment as long as the person remains in the kidnapper's power Impediment of Crime, bringing about the death of one's spouse, or the spouse of another, with the intention of marriageCode of Canon Law, Canon 1090 . Consanguinity, or close relationship by blood, even if the relationship is only by lawCode of Canon Law, Canon 1091 . Affinity, or close relationship by marriageCode of Canon Law, Canon 1092 .

Some of these laws can be relaxed by a dispensation before the ceremony. For example, Catherine of Aragon and Henry VIII of England received a dispensation from the impediment of affinity (Catherine had previously been married to Henry's brother Arthur, who died). Henry later based his request for annulment from Catherine (which largely led to the reformation of the Church of England) on the grounds that the dispensation was improperly given in that his father, Henry VII, had pressured the Archbishop of Canterbury into granting it.

The correction of this invalidity after the marriage requires first that the impediment has ceased or has been dispensed, and then a "convalidation" can take place or a sanatio in radice can be granted to make the marriage valid.

Consensual grounds for nullity A marriage may be declared invalid because at least one of the two parties did not give free and sufficient consent to marriage.

Grounds for nullity include: Simulation of consent; that is, the conscious and positive exclusion at consent by either or both of the contracting parties of marriage or one of the essentials of marriage: a) exclusivity of the marital relationship; b) the indissolubility of the marital bond; c) openness to offspring as the natural fruit of marriage (canon 1101§2) Deliberate deceit about some personal quality that can objectively and gravely perturb conjugal life, perpetrated for the purpose of obtaining consent (canon 1098) Conditional consent, if the condition at the time of marriage concerns the future, or if it concerns the past or present and is actually unfulfilled (canon 1102Note that consenting conditionally, even regarding past or present, is still illicit unless allowed by the ordinary) Force or grave fear imposed on a person to obtain their consent (canon 1103) A grave defect of discretion of judgment at consent concerning the essential matrimonial rights and duties mutually to be handed over and accepted (canon 1095 n.2) Psychic incapacity at consent to undertake the essential obligations of marriage (canon 1095 n.3). Error about the identity of the other spouse (c. 1097)

According to Canon 1095 a marriage can be declared null only when consent was given in the presence of some grave lack of discretionary judgment regarding the essential rights and obligations of marriage, or of some real incapacity to assume these essential obligations. This is verified only when a party was suffering from a serious psychic anomaly. Pope Benedict XVI in his address to the Roman Rota in 2009, echoing words of his predecessor John Paul II, has criticized "the exaggerated and almost automatic multiplication of declarations of nullity of marriage in cases of the failure of marriage on the pretext of some immaturity or psychic weakness on the part of the contracting parties". Calling for "the reaffirmation of the innate human capacity for matrimony", he insisted on the point made in 1987 by John Paul II that "only incapacity and not difficulty in giving consent invalidates a marriage".

Process Marriages declared null under the Catholic Church are considered as void ab initio, meaning that the marriage was invalid from the beginning. Some worry that their children will be considered illegitimate if they get an annulment. However, Canon 1137 of the 1983 Code of Canon Law specifically affirms the legitimacy of children born in both valid and putative marriages (objectively invalid, though at least one party celebrated in good faith). Critics point to this as additional evidence that a Catholic annulment is similar to divorce; although civil laws regard the offspring of all marriages as legitimate.

However, there are some significant differences between divorce and annulment. Divorce is concerned merely with the legal effects of marriage. Annulment, however, is also concerned with the reality of whether or not a true marriage was ever formed. This leads to the second difference. At least in most countries, divorce is always possible. However, not all applications for marriage nullity are granted.

An annulment from the Catholic Church is independent from obtaining a civil annulment (or, in some cases, a divorce). Although, before beginning an annulment process before an ecclesiastical tribunal, it has to be clear that the marriage cannot be rebuilt. Some countries, such as Italy, allow the annulment process to substitute for the civil act of divorce. In many jurisdictions, some of the grounds the Catholic Church recognizes as sufficient for annulment are not considered grounds for a civil annulment. In such cases, the couple will often need to be divorced by the civil authorities to be able to remarry in the jurisdiction. Once the Church annuls a marriage it would generally prefer that the marriage be subsequently annulled by the civil courts. However, should this not prove feasible, a civil divorce is acceptable.

If someone has been married previously and the first spouse is still alive, he or she must have received a declaration of nullity before entering into a marriage in the Catholic Church, even if neither party in the marriage was Catholic (privilege of faith being separate cases). The Catholic Church treats as indissoluble and valid every marriage when it is the first marriage for both parties. However, the church does not recognise as valid a marriage when one of the parties is Catholic but the marriage was not celebrated before a Catholic priest (unless a dispensation was first obtained).