As I understand it from my readings, the Frisians originated from the areas of Southern Scandinavia, Denmark and the mouth of the Oder. Up until 700 BC they are indistinguishable among the dolichocranic (narrow skull) and brachycranic (broad skull) found in that area.

Around 700 BC West Germans had settled into the coastal areas of northwest Germany. Here they can be divided along religious lines into 3 groups: Inguaeones, Istuaenes and Irmiones. The Frisians belong to the first group (together with Jutes, Warns, Angles and Saxons.) One other tribe in this area—the Chaukians—belongs in the Irminon group.

Inguaevones is derived from the god Inguz (another name for Freyr, the brother of Feya) which mythology has the Frisians descended from. The name (Freisias / Frisians) is derived from “Preisios” of the Indo-European root “prei” meaning to love.

Up until 400 BC, there is a fairly homogenic area (and please someone correct me if I am wrong) along the North Sea coastal areas. It is between 400-200 when this begins to change and by 200 a distinct Frisian culture is visible. This is a culture with not only narrow and broad skulls but even some non German peoples. You can see where they settled by the building of “terps” or mounds up until the fall of the Roman Empire.

If anyone knows more about these groups, tribes or places, please add on.