The Latin expression a latere, translated into legal vernacular as "at the side" or "sideways," designates the condition of collaterality or parallelism in various spheres of Law. In the scope of Family and Succession Law, it qualifies transversal kinship; in International and Contract Law, it refers to complementary instruments or agreements (side letters); and, in the General Theory of Procedure, it indicates elements or subjects that gravitate around the main dispute without occupying the central pole of the procedural legal relationship.
1. Definition, Concept, and Legal Nature
The term a latere has a polysemic legal nature, varying according to the branch of Law in which it is applied, but always maintaining the semantic core of "lateral proximity" or "secondariness." In Civil Law, specifically in Family Law, the expression is used to identify collateral or transversal kinship, that is, the one existing between people who come from a single ancestral trunk, without descending from one another (Art. 1,592 of the Civil Code).
From the perspective of Contract Law and International Law, the legal nature of the a latere institute manifests itself in the form of parallel or complementary agreements. These instruments aim to regulate details, interpretations, or conditions precedent that, for strategic or technical reasons, were not inserted into the main body of the treaty or contract (instrumentum), but which have binding force between the signatory parties.
2. Historical Origin and Evolution in Law
Historically, the expression dates back to Roman Law and, with special vigor, to Canon Law. The Legatus a latere represented the highest diplomatic dignity of the Holy See: a Cardinal sent by the Supreme Pontiff as his personal representative ("at his side"), endowed with full powers to act on specific missions. This figure consolidated the idea of an authority that, although not the principal one, acts with the same legal efficacy in a parallel sphere.
In Comparative Law, the Common Law system absorbed the concept through side letters, widely used in mergers and acquisitions (M&A) and investment funds. In the Brazilian legal system, the evolution of the term migrated from the strict definition of kinship to a hermeneutic application, being used by courts to describe arguments, evidence, or interveners that arise laterally to the main object of the lawsuit.
3. Legal Provision and Normative Framework
The most direct and codified application of the a latere concept in Brazil is found in the 2002 Civil Code (Law No. 10,406/2002):
- Art. 1,591: Defines kinship in a direct line.
- Art. 1,592: Establishes that "persons coming from a single trunk, without descending from one another, are relatives in a collateral or transversal line, up to the fourth degree." Classical doctrine calls this bond a latere kinship.
In the Code of Civil Procedure (Law No. 13,105/2015), although the expression does not appear ipsis litteris in the legal text, the institute of Assistance (Art. 119) and Amicus Curiae (Art. 138) reflect the intervention of third parties who act a latere of the original procedural relationship, defending a legal interest that may be reflexively affected by the decision.
4. Practical Application and Jurisprudential Understanding
The jurisprudence of the Superior Courts (STF and STJ) employs the term to delimit the extent of responsibilities and the validity of peripheral instruments. In the Superior Court of Justice (STJ), it is common to analyze a latere contracts in complex financial operations. The consolidated understanding is that such instruments are valid and binding, provided they do not contradict the social function of the contract or public policy norms.
In the Supreme Federal Court (STF), the expression is frequently used in votes to designate issues that, although they do not constitute the main petitum (claim), emerge "at the side" of the constitutional discussion, influencing the ratio decidendi. In tax matters, the STF has already ruled on the impossibility of taxing funds that transit a latere of the gross revenue, as they do not fit into the constitutional concept of revenue (RE 606.107/PR).
5. Related Principles and Doctrinal Divergences
The institute dialogues directly with the following principles:
- Principle of Legal Gravitation: Where the accessory follows the principal, but the a latere element may have autonomy depending on the agreement.
- Principle of Objective Good Faith (Art. 422, CC): Requires that a latere agreements be transparent and not serve to hide simulations or fraud.
The main doctrinal divergence lies in the efficacy of a latere agreements before third parties. One, more formalist, current argues that only the main instrument brought to registration produces erga omnes effects. Another, more modern current, aligned with Business Law, maintains that the efficacy of these instruments is full between the parties and must be respected by third parties who are aware of them, in compliance with the external protection of credit.
6. Contemporary Relevance and Practical Impacts
In contemporary times, the relevance of the a latere concept has been accentuated by the increasing complexity of legal relations. In Digital Law and Data Protection (LGPD), data sharing agreements often operate as a latere adjustments to the main terms of service. In Family Law, the discussion about socio-affective kinship creates a new layer of a latere relationships that challenges the rigidity of traditional consanguineous kinship.
It is concluded that the term a latere is not a mere Latin reminiscence, but an indispensable technical tool for understanding accessory, transversal, or parallel legal structures that, although they do not occupy the center of the debate, are essential for the integrity and exegesis of the legal system as a whole.
Legal and Jurisprudential References
- BRAZIL. Law No. 10,406, of January 10, 2002. Civil Code. Brasília, DF.
- BRAZIL. Law No. 13,105, of March 16, 2015. Code of Civil Procedure. Brasília, DF.
- STJ. Special Appeal No. 1,171,241/SP. Rapporteur Min. Nancy Andrighi. (Validity of collateral instruments in business contracts).
- STF. Extraordinary Appeal No. 606,107/PR. Rapporteur Min. Rosa Weber. (Concept of revenue and collateral funds).
- DINIZ, Maria Helena. Course of Brazilian Civil Law. Vol. 5: Family Law. São Paulo: Saraiva.
- PONTES DE MIRANDA, Francisco Cavalcanti. Treatise on Private Law. Tome IX. Campinas: Bookseller.
