Serfs were from everywhere, not just Africa. Slavs were the best….hence the word "slave" is named after them. But it was mainly germanic types who built a lot of the original settlements on the eastern seaboard back in the day. Then Irish and Italians and Poles, etc chipped in as they arrived in later decades. This country was not built on the backs of blacks. They just did not have the engineering skills but great laborers in hot climates that made the lily white western euros faint.