With an army of less than 35,000 men, but highly trained by Philip of Macedon, his father, Alexander, in only twelve years conquered ten of the most wealthy and populous countries of the world.

Caesar, Alaric, Attila, Charlemagne, and all the great military men from the greatest antiquity down to the present moment have trained and organized bodies of soldiers and sailors, under systems suited to the times, and then waged successful war on peoples less militarily efficient.
Cortez conquered Mexico, and Pizarro conquered Peru; the British, French, and Spanish subdued the Indians of North America, and during the latter half of the nineteenth century nearly all the land in the world that was "unoccupied" by Europeans or their descendants was taken in possession by European Powers.

Great Britain is now mistress of about one-quarter of the land and the population of the globe.

Russia, France, Germany, and the United States govern most of the remainder.
These results were brought about almost solely by the exercise of military force:--and of this force, physical courage was not a determining element, because it was just as evident in the conquered as in the conquerors.

The determining element was strategy that (under the behest of policy) prepared the military and naval forces in material and personnel before they were used, and directed their operations, while they were being used.
Of all the single factors that have actually and directly made the history of the world, the most important factor has been strategy..