There were five requirements for the acquisition of ownership by usacapio.

Usucapio was a concept in Roman law that dealt with the acquisition of ownership of something through possession.

Prior actual use is essential for the acquisition of ownership over a trademark pursuant to R.A. 166.

Doneau also made major contributions to various specialised areas of law such as the doctrine of possession and acquisition of ownership.

Ownership (limitation of ownership, acquisition of ownership, joint ownership)

Since mancipatio and in iure cessio were inherently public modes of acquisition of ownership, usucapio was the only private method of the ius civile.