Definition
A Latin term with two distinct legal meanings drawn from different legal traditions:
1. (Roman law) To act as an assessor — that is, to sit beside a magistrate or judge in an advisory capacity, assisting in the hearing and determination of legal matters. The term reflects the literal act of sitting alongside (ad + sedere) a judicial officer. Freed persons (liberti) were recognized as eligible to perform this function under Roman law.
2. (Medieval and early English practice) To assess, fix, settle, or reduce to certainty — whether in respect of time, number, monetary amount, quantity, or quality. In this procedural sense, the term appears in the compound phrase assidere, taxare et levare, meaning to assess, tax, and levy, describing the sequential steps in fixing and collecting a sum certain, as in the assessment of damages or costs.
Common Confusion
The two meanings of assidere, though sharing a Latin root, operate in entirely different legal contexts. The Roman law sense concerns personnel and judicial procedure — who may sit with a magistrate. The old practice sense concerns financial or quantitative determination — fixing an amount. A researcher encountering assidere in a source must identify whether the source is drawing on civilian Roman law or on medieval English practice, as the meanings are not interchangeable.
Why It Matters in Research
Assidere is a term of art that appears almost exclusively in Latin-language legal sources — Roman law texts, medieval English records, and early modern treatises citing both traditions. Researchers are most likely to encounter it in one of two contexts: (1) civilian or canon law scholarship discussing the assessor's role in Roman judicial administration, or (2) English records dealing with the assessment and levy of damages, fines, or costs, where the procedural phrase assidere, taxare et levare appears as a formulaic sequence.
The critical research trap is assuming the term has a single stable meaning across sources. Burrill's entry signals both meanings explicitly, but older digests and abridgments often cite only one without flagging the other. A Latin source using assidere in a damages context is not speaking to the composition of a Roman court, and vice versa.
For researchers working in the Law Mind corpus, assidere connects outward to the broader cluster of assessor-related terms (assessor, assidentes, taxare) and inward to discussions of Roman judicial structure. When encountered in English practice sources, it typically signals a writ or procedural entry dealing with the quantification stage of a judgment — the moment after liability is established and before execution. Understanding that assidere precedes taxare and levare in the formulaic sequence helps place a document within the correct procedural stage.
Historical Dictionary Support
Burrill's Law Dictionary is the primary historical dictionary source for this term. Burrill captures both meanings and provides the Digest citation (Dig. 1.22.2) for the Roman law sense, specifically the rule that freed persons may serve as assessors. He also preserves the compound phrase assidere, taxare et levare for the old practice sense, though his entry trails off at levare, suggesting the full entry was either abbreviated in transmission or incomplete.
No other historical dictionaries in the Law Mind shelf (Jacob's Law Dictionary, Tomlin's, Bouvier's) carry this term at the same level of detail. Researchers should treat Burrill as the controlling source here. The Roman law citation is genuine and traceable to the Digest title De officio adsessorum (D. 1.22), which concerns the qualifications and functions of assessors to magistrates.
Jurisdictional Note
Assidere is not a term of current positive law in any common law jurisdiction. Its relevance is historical and primarily confined to Roman law scholarship and medieval English legal records. Researchers in civilian jurisdictions (civil law countries with Roman law heritage) may encounter it in historical commentary on the assessor's role, which survived in modified form in various civil law court structures.