History begins when people begin to record it in some fashion. This is true with all cultures and in all times. The Siebenburgen Saxons story starts with an invitation. Geza II of Hungary needed people and issued an invitation to the German population to come and settle in his land. They did so over the next few centuries.
Geza had good reason to ask them to come. His land in the South was sparely populated and he needed more people to protect his borders. He came to the Hungarian throne as an eleven year old boy. His reputation as just king grew over the years. When he gave out the invitation, he was older and wiser and understood that the Tartars, Mongols, and Turks presented a threat to his country. He also needed money. Hoping to gain more taxes he invited people to populate the area “beyond the woods.”