The Picts, as they were known to their enemies, were a mixed group of peoples. The earliest inhabitants of the land were of the same stock as the Iberians, while another people started their migration from somewhere in northern India after the last glacial period abated, approximately 3000 to 4000 years ago. The latter were the Vanir or the "Beaker people" to archeologists. They moved to the west and stayed for a time in the Middle East, settling in the area north of the Black and Caspian Sea. They were matriarchal farmers and artisans, a predominantly peaceful folk. With the coming of more warlike Aesir peoples, also migrating to the west from India, the Vanir slowly moved northwesterly along the river which became known after them — the Don.
Eventually some of the Vanir moved across the sea, onto the land of Iberian folk of what is now Northern Scotland. They also settled in the present countries of Denmark, Norway, Sweden and Finland.
The Vanir brought with them the knowledge of working with metals, which the Iberian people lacked. The two peoples got along well together, for both were Matriarchal and the Vanir contributed agricultural knowledge the Iberians needed. For their part, the Iberians added ancient skills of woodworking, mining, medicinal plant lore, and magic. Indeed, you will find a great difference in tone and tenor in the "Hulder" — the name given to the Iberians by the Vanir — stories of the Vanir, and those "Faerie" tales of other cultures.
The Vanir and the Huldre were generally respectful, even helpful to each other. The Vanir were followed into that area much later by the Celtic peoples, who also migrated north along the Volga River. These Celtic peoples at first settled peacefully among the Vanir and Huldre, introducing new technologies to their new home.
Other migrations of Celts brought more warlike peoples, who tried to conquer the Vanir and the Huldre, but succeeded in only pushing them deeper into the northern wilderness. These people to were added to the makeup of the Pictish people. The Vanir and Huldre merged with these new peoples and became the people known as the Picts, who repulsed the advances made by the Romans and Scots, and dealt the Angle-Saxons the defeat at Dunnichen.