Bürgerliches Gesetzbuch
The indisputable main source of the Civil Code is the Siete Partidas (Seven-Part Code) of King Alfonso X, perhaps the pinnacle of Spanish "ius commune". For instance, in relating the acquisition of property, the code makes a clear distinction between the "titles" and the actual "acquisition" of property, similarly to the Roman Law and the German Bürgerliches Gesetzbuch.