In the earlier period of history dating back to about 9th century, the changing patterns of economic structures of European countries were closely related to changes in the forms of warfare to military service.
The word “mercenary” comes from the Latin word mercenaria meaning wages for soldiers for their military services. Going back to the system, it can be divided mainly in two categories: one category relates to the fight for a cause which may be religious or for national interests, the other is to fight for any individuals, groups, state or nation without any regard to national interests or issues, just for the sake of money or other facilities such as foods and shelters.
In the first category, the major role played by mercenaries was in the middle ages during Renaissance. For instance, the English and French mercenaries fought “Hundred Years’ war” during 1337-1453 The “Crusades” — a series of religious wars from the end of 11th century to 13th century organized by European powers to recover Christian holy places in Palestine is another example. In fact, from the earlier days of organized warfare, until the development of national standing armies in the mid-17th century, many countries frequently supplemented their military forces with mercenaries.
However, employment of mercenaries could be dangerous as well as economically expensive. For instance, in the early 14th century, the Byzantine Empire hired Spanish front-men to defeat their enemy — the Turks. Ultimately these mercenaries turned against their patrons and attacked several Byzantine towns at Magnesia (the modern Alasehir, Turkey).
During the 15th century, Swiss, German and Italian soldiers sold their services to various Western Princes and Dukes. These hired soldiers were often greedy, brutal and indisciplined. Much of their mutinous behaviour was the result of their Employers’ unwillingness or inability to pay for their salaries. The Spanish conqurors of Latin America as well as other colonial builders, sea adventurers, merchants and traders of the middle ages also employed these mercenaries for their defence as well as attacks.
By the end of the 18th century, mercenaries were however, more likely to be individual soldiers of fortune. The use of them was occasionally made. For instance, in the former Belgian Congo (now Zaire) mercenaries were engaged in the civil war — following the granting of independence in 1960.
Today, the engaged foreign mercenaries in most of their activities, are not confined in a particular region. This problem has become a global concern. Having been aided with most sophisticated war materials, they have in fact turned to be dreaded terrorists rather than an instrument for a cause.