Short answer. You must prove it. Article 1131 provides that for the purposes of prescription, just title must be proved; it is never presumed. Possession, however long and however open, establishes the possession and nothing at all about the title behind it, which is a separate matter entirely.

What the law says

For the purposes of prescription, just title must be proved; it is never presumed.

Civil Code, Article 1131 — Just Title Is Never Presumed. Read the full provision →

The rule closes a specific shortcut

A claimant who has been on land for decades naturally argues that so long an occupation must have started somewhere, and invites the court to assume a transaction it cannot see. Article 1131 refuses: just title must be proved; it is never presumed. The absence of a document is not neutral in this analysis, and it is not cured by the length or the openness of the possession. Nothing about having been on the land for thirty years says anything at all about how you came to be there.

What has to be proved

The thing itself is defined next door. Article 1129 says there is just title when the adverse claimant came into possession through one of the modes recognised by law for the acquisition of ownership, but the grantor was not the owner or could not transmit any right. Article 1130 adds that the title for prescription must be true and valid. So a genuine deed from a person who turned out not to own the land is just title; a forged or simulated instrument is not, and proving that it exists proves the wrong thing.

Whether you need it depends on your period

Article 1134 provides that ownership and other real rights over immovable property are acquired by ordinary prescription through possession of ten years, and that shorter route is the one requiring just title alongside good faith. Article 1137 allows acquisition through uninterrupted adverse possession for thirty years without need of title or of good faith. So a claimant who cannot prove a title is not necessarily lost. He is on the long road, and the evidence he has to assemble is about the possession instead.

Produce the transaction, not the occupation

The instrument itself and its date, the identity and capacity of the person who granted it, proof of the price paid, and any record of the transfer made at the time. If the original is gone, the loss and the search for it become part of what must be shown, which is far harder than keeping the paper would have been. Tax declarations, improvements and testimony from neighbours prove possession. They do not prove a title, and offering them for that purpose is how these claims fail.

Related provisions

Note. Statute text quoted on this page is reproduced from the official enactment and is linked to the full provision. The explanation around it is general legal information from Vivas & Nobles Law Office, not legal advice. Whether it applies to your situation depends on facts only a lawyer reviewing them can assess.