 It offered great protection against cavalry – still the dominant fast-attack arm on the battlefield – and was extremely sturdy and difficult to defeat.It was very hard to isolate or outflank and destroy a tercio by maneuver due to its great depth and distribution of firepower to all sides (as opposed to the maximization of combat power in the frontal arc as adopted by later formations).The individual units of pikemen and musketeers were not fixed and were re-ordered during battle to defend a wing or to bring greater fire power or pikes to bear in a certain direction.