Roman Accession

Accession in relation to land

Buildings (Inaedificatio)

Where X built on X's land using Y's materials, X owned the house since it acceded to X's land. Y would be capable of laying ONE of two actions if X was in good faith (bonas fides) in using Y's materials, but TWO actions if X was in bad faith (mala fides). These actions were (i) the vindicatio for the materials and (ii) the actio de tigno, which would recoup twice the value of the materials. Additionally, Y would also have an action against a third party if that third party stole the materials.

Where X built on Y's land using X's materials, Y owned the house since it acceded to Y's land. If in bad faith, X was presumed to have made a gift of the materials to Y and would thus have no action. If X was in good faith, and additionally was in legal possession of the house, then any vindicatio brought by Y could be defeated by X using the defence of fraud (exceptio dolus malus) until Y paid X for the materials. It is possible that if X was in good faith, then X could remove items that would not damage the building, e.g. gates. This was known as the ius tolluendi and was possibly established under Justinian.

Buckland, in his Textbook of Roman Law, discusses a third situation where X builds on Y's land using Z's materials. In such a situation, Buckland suggests that in relation to Y, X should be treated as though an XYX situation has occurred, and in relation to Z, as though an XXZ situation has occurred.

Plants and seeds

Rivers and new islands

• Alluvion
• Avulsion

Accession in relation to movables

1. Economic value
2. Size
3. Physical identity
4. Relative non-economic value in terms of aesthetic value, or labour, etc.

In Roman Law, there was no consistency. Everything was decided on a casuistic basis. The Physical Identity test was the dominant test, i.e. the principal is that which gives its name to the final product and the accessory is that which has its identity merged and lost in the identity of the other. However, there are a number of special cases with special, and rather idiosyncratic rules, which are as follows:

1. Writing (scripture) and painting (pictura)
2. Threads and garments (textura)
3. Confusio and commixtio

Other meanings

• In the context of Public International Law the term accession may refer to the act of joining a treaty by a party that didn't take part in its negotiations, as defined by article 15 of the Vienna Convention on the Law of Treaties. It is commonly used as a synonym of ratification, acceptance or approval and occurs whether the treaty is open to the participation of new member states by mean of an accession provision or whether all the other members so agree. In the first case accession implies a direct participation of the new member state in the treaty, without any modification of the original agreement. In the latter, accession by a new member state implies a new agreement between all member parties. Such as when a new member state joins the European Union (see Enlargement of the European Union).
• In a historical or constitutional sense, the term accession is applied to the coming to the throne of a dynasty or line of sovereigns or of a single sovereign.
• In a Real Estate context, the term accession is applied to the act of physically attaching a personal property to land (real property), thus converting it into a fixture. (I.e. Installing an air conditioner in a house.) Opposite of severance.
• "Accession" sometimes likewise signifies consent or acquiescence. Thus, in the bankruptcy law of Scotland, where there is a settlement by a trust-deed, it is accepted on the part of each creditor by a "deed of accession."
• In a museum, an object is accessioned into the collection when it becomes the legal property of the museum, it is assigned a catalogue number, and formal information about its provenance is noted and recorded. (When the museum disposes of the object, it is formally "de-accessioned" from the collection.)
• A book or other object is accessioned into a library, similar to the process in a museum.
• A biological sample is accessioned into a clinical laboratory when the clinical laboratory establishes control over the sample. Typically an accession number is assigned at this time.
• In the context of bioinformatics, an accession refers to a unique identifier given to a biological polymer sequence (DNA, protein) when it is submitted to a sequence database. See accession number.

References