Origen latino de «en lugar de» y «en vez de»

[EN] The study of prepositional phrases, that is, the linguistic resource that allows to increase the list of prepositions, has become prominent in most modern languages. Their origin, however, is generally neglected. In this paper we will deal with the Latin origins of two Spanish prepositional phrases «en lugar de» and «en vez de» that both mean ‘instead of’, that is, they express the replacement of one entity by another. As we will show in this contribution, the former comes from the Latin expression in locum/in loco + genitive, whereas the latter has its origin in in vicem/in vice + genitive.