It has been a commonly held historical belief that in the second half of the 17th century, the Spanish army suffered such catastrophic defeats that it effectively brought about the collapse of the state as a major player on the European stage. The wars, fought out in Catalonia, Franche Comte, Flanders and Italy, resulted in a series of substantial defeats for Spain. The forces of Louis XIV carried all before them. Spain's ability to fend off the French monarch's assault was not eased by the fact that, at the same time, Spain had faced the Portuguese in the Iberian Peninsula, the English in the Caribbean, the Algerians in Melilla, as well as further insidious French assault in southern Italy and in the colonies. In this regard, it would be more correct to consider this age as a period of resilience, rather than military defeats. Equally superficially, the Portuguese War of Independence too was considered as a peripheral conflict of minor interest, while it also involved France and England in addition to the countries directly concerned.

The story, organisation, uniforms and equipment of the Spanish and Portuguese armies of this age are dealt for the first time in a single book, after archive's sources and unpublished iconography.