Definition of Feudorum libri
The Books of Feuds published during the reign of Henry III, about the year 1152. The particular customs of Lombardy as to feuds began about the year 1152 to be the standard of authority to other nations by reason of the greater refinement with which that branch of learning had been there cultivated. This compilation was probably known in England, but does not appear to have had any other effect than to influence English lawyers to the more critical study of their own tenures, and to induce them to extend the learning of real property so as to embrace more curious matter of similar kind.
That's the definition of Feudorum libri in Black's Law Dictionary 6th Edition. Courtesy of Cekhukum.com.