Nomadic people received income from where

Selling livestock, and making handicrafts, such as pottery.

Explanation:

Nomadic people are members of a community of people without fixed homes who often move to and from the same areas, in search of food, water, grazing. They include nomadic hunter-gatherers, pastoral nomads who owns livestock, and tinker or trader nomads. They make their living through selling the livestock while some make handicrafts such as pottery for sale.

your answer is

to dominate europe

and i know for a fact it can't be the others

idk you know what i mean hahahaha