nevertheless since both peoples feared and hated morgoth they made alliance , and had of it great profit ; for the naugrim learned many secrets of craft in those days , so that the smiths and masons of nogrod and belegost became renowned among their kin , and when the dwarves began again to journey into beleriand all the traffic of the dwarf-mines passed first through the hands of caranthir , and thus great riches came to him .