Toward Combined Arms Warfare:- A Survey of 20th~Century Tactics, Doctrine, and Organization

The concept of Combined Arms” has existed for centuries, but
the nature of the combination and the organizational level at
which it occurred have varied greatly. Prior to the seventeenth
century, for example there was often no need to combine
infantry, artillery, and cavalry at the small-unit level. Each
branch served a specific function on the battlefield, and only
the senior commanders present needed to coordinate the effects of
the different arms. In succeeding centuries, the general trend
has been to combine the arms at progressively lower levels of
organization. The concern of commanders has gone from
coordinating the separate actions of separate arms, to gaining
greater cooperation between them, and finally to combining their
actions to maximize the effect of their various properties.