occupatio

Occupatio is a Latin legal term used in Roman law to describe the acquisition of ownership by occupying a thing that has no owner, i.e., res nullius. The core idea is that ownership can vest in the first person who takes possession with the intention to possess as one’s own. Occupation traditionally applied to tangible, capturable property that is not currently owned, such as wild animals, birds, fish in the sea, or other unowned goods.

The essential elements are: (1) the object must be res nullius; (2) there must be actual taking possession; and (3) there must be the intention to own. When these conditions are met, ownership passes to the occupier. The rule did not apply to things that already had an owner or to intangible rights.

In the broader history of property law, occupatio influenced later theories of acquiring ownership and informed the development of civil-law approaches to possession and acquisition. In modern practice, occupancy as a distinct doctrine has largely been superseded in many jurisdictions by usucapion (long or adverse possession) and by statutory rules governing lost or abandoned property, but the underlying notion remains a foundational concept: possession can confer title under appropriate circumstances.

See also: res nullius, usucapio, possession (law).