imprescriptible obligations

in the Scots law of prescription and limitation, certain rights and obligations cannot be affected by the passage of time: any real right of ownership of land, the right in land of the lessee under a recorded lease; any right to recover property extra commercium; the trustee's obligation to make reparation for breach of trust or to make over trust property; the obligation of a mala fide holder of property to restore it; the right to recover stolen property from a thief or a party to the theft; the right to be served as an heir to an ancestor; any right res merae facultatis.