Forbidden from owning land, these people became successful merchants in Europe during the Middle Ages.

Jews in the middle ages

Explanation:

Middle Ages witnessed a boom in commercial activities which led to an increasing need for money exchange and currency conversion. Large amounts of money were soon collected and exchanged by money changers, and loans were provided to merchants. A big barrier to bank development in the Middle Ages has been the ban of usury by the Church. Because Jews were prohibited from holding land or engaging in more adequate sources of the economic venture, the profession of money-changers were generally taken up by them.

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explanation:

the correct answer is:   the domino theory states that if one country in a region came under the influence of communism, then the surrounding countries would follow in a domino effect.