A brocard is a legal principle expressed in Latin (and often derived from past legal authorities or Roman Law), which is traditionally used to express concisely a wider legal concept or rule. The name comes from the Latinized name of Burchard (died 1025), bishop of Worms, Germany, who compiled 20 volumes of Ecclesiastical Rules.
Begun in 1008, the materials took Burchard four years to compile. He wrote it while living in a small structure on top of a hill in the forest outside Worms, after his defeat of Duke Otto and while raising his adopted child. The collection, which he called the "Collectarium canonum" or "Decretum", became the primary source for canon law.
Along with numerous documents from a variety of sources, including the Old Testament and Augustine of Hippo, Burchard included the Canon Episcopi in this collection, under the belief that it dated from a bishop's "Council of Anquira" in 314, but no other evidence of this council exists. Because of this inclusion, Burchard has been described as something of a rationalist. As the source of canon law, Burchard's Decretum was supplanted around 1150 by the Decretum Gratiani, a much larger collection that further attempted to reconcile contradictory canon law.
Burchard spent the years 1023 to 1025 promulgating "Leges et Statuta familiae S. Petri Wormatiensis", a collection of religious laws he endorsed as fair and hoped to see adopted with official approval.
- Dura lex, sed lex
- "The law [is] harsh, but [it is] the law". It follows from the principle of the rule of law that even draconian laws must be followed and enforced; if one disagrees with the result, one must seek to change the law.
- Ignorantia legis non excusat
- "Ignorance of the law is no excuse." Not knowing that one's actions are forbidden by the law is not a defense.
- In claris non fit interpretatio
- When a rule is clearly intelligible, there is no need of proposing a (usually extensive) interpretation.
- Inadimplenti non est adimplendum
- "One has no need to respect his obligation if the counter-party has not respected his own." This is used in civil law to briefly indicate a principle (adopted in some systems) referred to as the synallagmatic contract.
- lex specialis derogat legi generali
- "A law governing a specific subject matter overrides a law which only governs general matters."
- Iura novit curia
- The judge knows the law (technically, there is no need to "explain the law" or the legal system to a judge/justice in any given petition).
- Nemo dat quod non habet
-  The basic rule that a person who does not own property (e.g. a thief) cannot confer it on another except with the true owner's authority (i.e. as his agent). Exceptions to this rule include sales under statutory powers and cases in which the doctrine of estoppel prevents the true owner from denying the authority of the seller to sell.
- Nullum crimen, nulla poena sine praevia lege poenali
- There can be neither crime nor punishment unless there is a penal law first.
- Pacta sunt servanda
- Contracts are the law or Contracts establish obligations (between those who sign them).
- Quod non est in registro, non est in Mundo
- What is not reported in the (related, referring) registry, has no legal relevance. Used when a formal act (usually a recording or a transcription) is required in order to give consistence, content or efficacy to a right.
- Res inter alios acta vel iudicata, aliis nec nocet nec prodocet
- What has been agreed/decided between people (a specific group) can neither benefit nor harm a third party (meaning: two or more people cannot agree amongst each other to establish an obligation for a third party who was not involved in the negotiation; furthermore, any benefit that may be established will have to be accepted by the third party before it can be implemented).
- Sententia quae in rem iudicatam transit, pro veritate habetur
- When a definitive sentence is declared, it is considered to be the truth. In the case of a sentence in rem iudicatam (that finally consents to consider a judgement completed), its content will then be the only legally relevant consideration of a fact.
- Solve et repete
- Respect your obligation first, then you can ask for reimbursement. Used in those situations in which one of the two (or more) parties needs to complete his obligation before being allowed to ask for the opposite obligation to be respected by his counter party. Usually this principle is used in fields and subjects in which a certain general steadiness or uniformity of the system has been considered a relevant value by the legislator. The case is typical of service contracts with repeated obligations (like with gas, water, electricity providers and similars), in which irregularities on one side cannot be balanced if not in a regular situation (i.e., of payments) on the other side. The customer, for example, might be asked to pay regularly the new bill, before contesting the previous one in which he found irregular calculations, and asking for a balancement with newer bills; he thus cannot by himself determine a discount in the next payment.
- Ubi lex voluit, dixit; ubi noluit, tacuit
- When the law wanted to regulate the matter in further detail, it did regulate the matter; when it did not want to regulate the matter in further detail, it remained silent (in the interpretation of a law, an excessively expansive interpretation might perhaps go beyond the intention of the legislator, thus we must adhere to what is in the text of the law and draw no material consequences from the law's silence).