In Roman law scholarship the view prevails that there was no retention of title clause (pactum reservati dominii), this clause is considered being rather an invention of medieval ius commune. This view is correct given the fact that retention of title was ineffective from the point of view of Roman law insofar as the buyer, being also the possessor, could always acquire ownership by means of prescription (usucapio) since the requirement of good faith was normally fulfilled. The Roman lawyers devised, therefore, several constructions which made sure that the buyer only acquired mere detention of the sold cattle in order to the exclude his acquisition of possession thereby eliminating looming danger of usucapio. This "retention of possession" is the functional equivalent of modern retention of title.