Legal Principles of Capture and Accessio

Effective control constitutes capture for wild animals. For example, if you trap a wild animal, you've captured it.

A wild animal becomes res nullius (no owner) if it escapes the owner's control. For example, if your pet escapes its cage, it's once again wild.

In Roman Law, a writing such as lettering or a contract, added to a scroll would become part of the scroll, which was the main material, because the writing itself didn't overshadow the scroll in terms of perceived value.

According to the Roman law concept of accessio, a painting would not become part of the canvas because the painting overshadows the canvas in value. The canvas would therefore not be seen as the principal object.

If someone uses another person's materials to create something new, and the materials become inseparable from the new work, the owner of the materials loses ownership of the original material, but they may be able to claim compensation for the original material.

In Roman Law, when someone sews a button onto their garment, the button doesn't become part of the garment due to the fact that it's easy to remove. Ownership of the button remains with the original owner.

In Roman Law, if someone builds a house on land that belongs to another person, the owner of the land also owns the house. However, the builder still retains ownership of the materials used to build the house. This is applicable even in situations where the builder acted in good faith.

In Roman Law, 'textura' is the principle that when someone uses another person's materials to create something new, and the materials become inseparable from the new work, the creator of the new work becomes the owner of both the new work and the original materials.

A mistaken reason for transferring ownership. It's not a legitimate reason, but it might still be acceptable under certain circumstances.

The delivery of a thing by the transferor to the transferee, but the transferor retains temporary possession or control.

The transferor authorizes the transferee to keep a thing that the transferee already possesses. This declaration of authorization is the delivery.

The point where a property, in view of the parties, can be considered as being delivered.

A building constructed on one's own land becomes the property of the landowner, even if the materials used belong to another.

The owner of materials incorporated into a structure retains ownership of those materials, but cannot reclaim them through legal action while they are part of the structure.

If someone builds in bad faith (knowing the materials are stolen), the rightful owner can sue for double the value of the stolen materials. This action is called actio de tigno iniucto.

When one thing is added to another, it may or may not become part of the original object. This concept, called accession, is determined by whether the added item becomes an inseparable part of the original.

In accession, if the added item becomes an inseparable part of the original, it belongs to the owner of the original object. This principle applies to painting, writing, etc.

If the added item is added in good faith, but the adder is out of possession, they have no legal recourse to reclaim the added item. However, if they are in possession, they can claim compensation for the value of the added item.

If the added item is added in bad faith, it is considered a gift to the owner of the original object.

When materials from different owners are combined to create a new, distinct object, the concept of specificatio applies. The maker of the new object generally acquires ownership.

In specificatio, if the maker of the new object used some of their own materials, they are considered the undisputed owner of the new object.

If the maker of the new object acted in bad faith, they could be sued for theft but still retain ownership of the new object.

If the maker of the new object acted in good faith, but the owner of the materials is out of possession, they can reclaim the new object through vindicatio, but they must compensate the maker for the value of the materials used.

When an object made from another object cannot be easily returned to its original form, it is considered irreducible. In such cases, the maker of the new object becomes the owner, according to Justinian's doctrine.

Treasure found on someone's land is subject to different ownership rules depending on the circumstances of the discovery: by accident, intentionally, or by ancient tradition.

When different substances are mixed together, it's called confusio. If the resulting mixture is not a new object (nova species), the owners of the original substances retain ownership proportionally to the value of their contributions.

A bona fide possessor (someone who believes they own the property) owns the natural fruits that fall from the property. If they discover they don't own the property, they lose ownership of the fruits.

A usufructuary (someone with the right to use a property but not own it) does not own the natural fruits of the property. They only gain ownership if they pick them themselves.

Traditio of res mancipi, while giving possession, does not grant full ownership. It grants bonitary ownership, which can be converted to full ownership through usucapio.