Contemporary opponents of papal powers in Italy emphasized the primacy of civil law and civil jurisdiction, now firmly embodied once again in the Justinian "Corpus Juris Civilis". The Florentine chronicler Giovanni Cavalcanti reported that, in the very year of Valla's treatise, Filippo Maria Visconti, Duke of Milan, made diplomatic overtures toward Cosimo de' Medici in Florence, proposing an alliance against the pope. In reference to the "Donation", Visconti wrote: "It so happens that even if Constantine consigned to Sylvester so many and such rich gifts – which is doubtful, because such a privilege can nowhere be found – he could only have granted them for his lifetime: the empire takes precedence over any lordship."