Definition
Ciatur is a Latin term from Roman law denoting a servitude obligating a neighboring landowner not to obstruct or darken another's windows or light openings. Under this servitude, the burdened party is prohibited from erecting structures — buildings, walls, or other obstructions — that would block the flow of light to the dominant tenement's windows. It functions as a negative servitude: it does not grant the holder an affirmative right to use another's land, but rather restrains what the neighboring owner may do on their own.
In substance, ciatur is the Roman law ancestor of what Anglo-American property law calls an easement of light, or ancient lights.
Why It Matters in Research
Researchers encounter ciatur almost exclusively in two contexts: Roman law materials and older common law treatises that trace the origins of easements of light. The term itself does not appear in modern American or English statutory law, but understanding it is essential for following the conceptual chain from Roman servitudes through civil law systems to the common law doctrine of ancient lights.
A key trap for historical researchers: ciatur appears in citations to Justinian's Institutes (2, 3, 4) referencing the classification of urban praedial servitudes. When reading 18th- or 19th-century property treatises that discuss ancient lights or light-and-air easements, authors often invoke Roman servitude categories — including ciatur — as doctrinal foundation. The presence of this Latin terminology does not mean Roman law governed the outcome; it signals that the author is constructing historical legitimacy for a common law rule.
In civil law jurisdictions (Louisiana, Quebec, and in comparative law research), servitudes of light descend more directly from the Roman framework and ciatur's conceptual content remains more operative. In those materials, the Roman taxonomy matters substantively, not merely rhetorically.
Researchers working on the historical development of light easements, neighbor law, or the reception of Roman property concepts in Anglo-American law will find ciatur appearing as a doctrinal anchor point rather than a working legal term.
Historical Dictionary Support
Black's Law Dictionary defines ciatur as "a servitude not to hinder lights; the right of having one's lights or windows unobstructed or darkened by a neighbor's building, etc." with a citation to Justinian's Institutes 2, 3, 4. This is the standard treatment: a brief, accurate Roman law gloss.
Historical legal dictionaries are consistent in treating ciatur as a term of Roman and civil law with no independent English common law career. What the historical sources do not address — and what researchers should note — is the divergence between the Roman servitude system, which categorized ciatur as an urban praedial servitude running with land by operation of law or agreement, and the English doctrine of ancient lights, which arose through long use and was treated as a form of prescriptive easement. The doctrinal mechanisms differ substantially even where the practical outcome — protecting a landowner's access to light — is the same. Historical dictionaries elide this distinction by treating ciatur as simply the Roman label for the same concept, which can mislead researchers into overstating the continuity between Roman and English law on the point.
Jurisdictional Note
Ciatur as a working legal concept is confined to civil law systems and historical scholarship. In common law jurisdictions, the functional equivalent is the easement of light or ancient lights doctrine, which is largely abolished or severely curtailed in the United States but survives with more force in English law. Civil law jurisdictions with Roman roots may use this or cognate terminology in doctrinal discussion of light servitudes.