Usucaption and the property register

In the Spanish system, when a contract causes the legal-real transfer, we follow the theory of the title and the mode, thus moving away from the consensual model adopted in Italian law, in which the mere conclusion of the title is sufficient for the transfer to be understood to have taken place. In other words, under Spanish law, the transfer is not considered to have taken place until the delivery of the thing that is the object of the contract. On the other hand, it is optional to register the business in the Land Registry (i.e. registration is declaratory and not constitutive). But what happens when the person transferring the right is not the rightful owner? In these cases, to remedy the transferor's lack of ownership, usucapion comes into play, which is one of the original ways of acquiring property and other rights in rem under Spanish civil law based on possession. As usucapion can operate outside the Land Register, mismatches will likely arise between what is reflected in the Register and the extra-registered reality. In this paper, we analyse precisely the response that the Spanish mortgage legislation, through the current articles 35 and 36 LH, has tried to offer to the different questions that emerge when the reality of the register and the extra-registered (or possessory) reality come into conflict.