Before revision: History Before the colonization by the French of the Maghreb and Sahel countries in which they dwell , the nomadic Tuareg federations chose a chief among the wise men of the tribes to rule the loose union of closely related groups .
After revision: History Prior to the colonial period in the Maghreb and Sahel countries in which theiry dwell , the nomadic Tuareg federations chose a chief among the wise men of the tribes to rule these confederaciesfrom .