Hi Jim,
Greetings from Portugal

.
So we were called Frangues, Franguis, Fringuins, Fringis, Firinghee; there were even places in Madras, formerly inhabited by Portuguese, called Fringe Burane and Feringhi or Frangula Dibba ...
But i found no evident link between those and the discussed (mark on blades) Fringia

.
Fernando