If from this extreme we take the opposite direction, we find that the smaller the mass of troops in one column the greater the ease and precision with which the march can be performed. The result of this is the need of a _division_ quite irrespective of that division of an army in separate parts which belongs to its position; therefore, although the division into columns of march originates in the strategic disposition in general, it does not do so in every particular case. A great mass which is to be concentrated at any one point must necessarily be divided for the march. But even if a disposition of the army in separate parts causes a march in separate divisions, sometimes the conditions of the primitive disposition, sometimes those of the march, are paramount. For instance, if the disposition of the troops is one made merely for rest, one in which a battle is not expected, then the conditions of the march predominate, and these conditions are chiefly the choice of good, well-frequented roads. Keeping in view this difference, we choose a road in the one case on account of the quarters and camping ground, in the other we take the quarters and camps such as they are, on account of the road. When a battle is expected, and everything depends on our reaching a particular point with a mass of troops, then we should think nothing of getting to that point by even the worst by-roads, if necessary; if, on the other hand, we are still on the journey to the theatre of war, then the nearest great roads are selected for the columns, and we look out for the best quarters and camps that can be got near them. Whether the march is of the one kind or the other, if there is a possibility of a combat, that is within the whole region of actual war, it is an invariable rule in the modern art of war to organise the columns so that the mass of troops composing each column is fit of itself to engage in an independent combat. This condition is satisfied by the combination of the three arms, by an organised subdivision of the whole, and by the appointment of a competent commander. Marches, therefore, have been the chief cause of the new order of battle, and they profit most by it.