Abstract
The main aim of this article is to present interpolations with respect to acquiring ownership by long possession. Byzantine emperor Justinian, instigator of the most famous codification of Roman law known as the Corpus iuris civilis, reformed many civil law institutes including usucapio and praescriptio longi temporis.
He substantially changed relationship between both institutes, ways of application as well as period of time required for the purpose of acquiring ownership. As sentences written by old Roman jurists did not reflect these reforms, Justinian commanded to modify them in order to keep Digesta seu Pandectae easily applicable.
It is possible to identify these changes, classify them and discover reasons, why they were inevitable. The article brings few examples.