Montesquieu

Several capi­tu­la­ries were appen­ded to the law of the Lombards, to the Salic laws, and to the law of the Bavarians. The rea­son has been sought ; it is to be found in the thing itself. There were seve­ral sorts of capi­tu­la­ries. Some rela­ted to poli­ti­cal govern­ment, others to eco­no­mic govern­ment, most to eccle­sias­ti­cal govern­ment, and some to civil govern­ment. Those of this last sort were appen­ded to the civil law, in other words, to the per­so­nal laws of each nation : that is why it is said in the capi­tu­la­ries that nothing has been sti­pu­la­ted there against Roman law.1 Indeed those which regar­ded eco­no­mic, eccle­sias­ti­cal, or poli­ti­cal govern­ment had no rela­tion to that law ; and those which regar­ded civil govern­ment rela­ted only to the laws of the bar­ba­rian peo­ples which were being explai­ned, cor­rec­ted, aug­men­ted and redu­ced. But these capi­tu­la­ries appen­ded to per­so­nal laws I think cau­sed peo­ple to neglect the body itself of the capi­tu­la­ries : in times of igno­rance, the sum­mary of a work often spells the end of the work itself.

See Edict of Pistres, art. 20.