Mercenary: Definition & Historical Organizations

Instructor: Matthew Helmer

Matt is an upcoming Ph.D. graduate and archaeologist. He has taught Anthropology, Geography, and Art History at the university level.

Mercenaries are professional soldiers hired to fight alongside foreign armies. They have been employed in historical battles for millennia. This lesson reviews the historical roots of mercenaries, major organizations, and their legacies today.

What is a Mercenary?

Why would someone fight for a cause which is not necessarily their own? For centuries, mercenaries have risked death for financial or personal gain, and they have been pivotal forces in some of the world's most important historical battles. As highlighted below, mercenaries are still controversial figures in modern warfare, including in the United States.

Early Historical Accounts

For much of the ancient world, fighting as a mercenary was a lucrative source of income, as well as an opportunity for adventure, despite obvious risks. In fact, mercenaries are often called the world's second oldest profession. Some of the earliest accounts of mercenary use date back to ancient Egypt during the 13th Century BC. The ancient Greeks also relied heavily upon mercenaries, who came from as far away as Celtic settlements in Britain. In many instances, mercenaries would wind up fighting against their home countrymen. For example, historical accounts document the use of over 10,000 Greek mercenary forces by the Persians against Alexander the Great.

Mercenaries of Western Europe

Swiss Guard
Swiss Guard

Mercenaries were especially popular in Europe during the Early Modern Period, between the Middle Ages and the late Renaissance. Small nations, religious divisions, and land disputes created a thriving market for mercenary forces. The Swiss were key providers of mercenaries throughout Europe, providing highly trained soldiers in spear and pike regiments. Today, the Swiss Guard, the longest surviving Swiss mercenary unit, protects key places, such as the Vatican.

As Nation-States developed throughout Europe, civilian armies became preferred over mercenary forces. One of the main reasons for this was the longstanding belief that mercenaries were a dishonorable profession, and employing them within wars was looked down upon. Laws outlawed many mercenary forces, with the exception of key regiments, such as the Swiss Guard. Nevertheless, mercenaries continued to be employed throughout the colonial era. Notably, Great Britain employed Prussian mercenary forces against the United States in the Revolutionary War.

Continued Controversy: The Legacy of Mercenaries Today

French Foreign Legion
French Foreign Legion

After a period of decline, mercenaries have had a resurgence in western warfare. One of the largest existing mercenary groups in the world today is the French Foreign Legion, who began approximately 150 years ago. The French Foreign Legion is made up of soldiers from over one hundred nationalities, who are offered French citizenship and asylum in return for military service. The Legion has fought mainly in French colonies, but also in both World Wars, and continues to be used in conflicts in Africa and the Middle East.

To unlock this lesson you must be a Member.
Create your account

Register to view this lesson

Are you a student or a teacher?

Unlock Your Education

See for yourself why 30 million people use

Become a member and start learning now.
Become a Member  Back
What teachers are saying about
Try it risk-free for 30 days

Earning College Credit

Did you know… We have over 200 college courses that prepare you to earn credit by exam that is accepted by over 1,500 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.

To learn more, visit our Earning Credit Page

Transferring credit to the school of your choice

Not sure what college you want to attend yet? has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.

Create an account to start this course today
Try it risk-free for 30 days!
Create an account