What is "pieres"

The '''Pieres ' ( Ancient Greek,"Πίερες") were a Thracian tribe connected with the Brygi, that long before the archaic period in Greece occupied the narrow strip of plain land, or low hill, between the mouths of the Peneius and the Haliacmon rivers, at the foot of the great woody steeps of mount Olympus. This region was named after them as Pieria ( Ancient Greek,"Πιερία''").