In this memorandum from April 1866 on a possible war between Prussia and Austria, Helmuth von Moltke (1800–1891) describes the most efficient means of deploying military formations to the front and outlines how railroads could be used to offset inferior Prussian troop strength. The following passage emphasizes the need for greater railway transportation capacity and points to the beneficial effects of rapid mobilization—factors that actually contributed to the Prussian victory that summer.

Helmuth von Moltke, Memorandum on a Possible War between Prussia and Austria (1866)

  • Helmut von Moltke


Memorandum, Berlin, April 2, 1866

As a political question, war against Austria, its probability or inevitability, lies outside the scope of my assessment. From my point of view, however, I believe I must express the conviction that the success or failure of this war depends essentially on the decision [for war] being made earlier here than in Vienna and, if possible, right now.

One advantage for us, which cannot be overstated, is that we can move our army along five railroad lines and thus have it essentially concentrated along the Saxon-Bohemian border in 25 days.

Austria has just one railway line to Bohemia and will need 45 days to assemble 200,000 men after withdrawing the troops already there and in Galicia, and assuming that its cavalry is already on the march.

If Bavaria stands by Austria, it is not so much Bavaria’s army as the use of its Regensburg-Pilsen-Prague railway line that is detrimental to us, since this shortens the above-mentioned Austrian concentration by about 15 days.

If the Prussian army is ordered to mobilize even now, Bavaria, which is so little prepared for war, will in all probability not have finished arming, mobilizing and concentrating its 40,000 or so men near Bamberg when the first battle between Austria and Prussia is fought. The purpose of the deployment of the Bavarian armed forces is not so much to besiege Coblenz and Cologne, or even Erfurt, and to seize Prussian territory, but rather to wait for success and then join the victor as an armed power.

For us it is a matter of defeating only the one enemy, Austria, and for this we must muster all our forces, and if anyone should ask for my opinion, we will have to use not only the 7th but also the 8th Army Corps.

If we take possession of Mainz, as is then necessary, we have in this place, in Coblenz, Cologne, and Erfurt, strongholds that can be defended mainly by the Landwehr [territorial reserves], so that even the improbable invasion of the Rhine Province or Thuringia by the South Germans cannot be of any consequence as soon as we have dealt with Austria. Moreover, the 7th and 8th Army Corps threaten Munich more directly if they advance to Prague than if they are concentrated at Mainz.

If, in view of Bavaria’s military situation, we at least manage to prevent the use of the Regensburg railway for Austrian troop transports (which would really be a hostile measure against us), then we will still have the decisive advantage of the initiative in the event of an immediate mobilization of the army.

If Austria wants an alliance with Saxony, it cannot avoid the requirement to help defend the country; otherwise, the Dresden cabinet would seek a separate peace at the last moment. We shall reach Dresden with the 4th, 7th, 8th, and Guards Corps on the 31st day with over 100,000 men.

If everything that is now available in Bohemia goes to support Saxony, then we would only encounter 74,000 men there. For with only one railway line, it would not be possible, by the designated point in time, to assemble more than 100,000 Austrians from the military frontier, from Hungary and Galicia, and these would necessarily have to fight against our 1st, 2nd, 3rd, 5th, and 6th Corps, over 150,000 men.

We would thus have the prospect of striking the first blows in Bohemia and Saxony from a position of significant superiority.

If, on the other hand, the use of the Bavarian railroad line is granted to the Austrians, then he following numbers can be available on the designated 31st day:

from Hungary and Austria


[+] from Galicia



182,000 men

[+] as reinforcements to existing forces

50,000 men

[+] conscripted and including Saxons

24,000 men

[=] putting the entire army at

256,000 men

[–] and after deducting the garrison forces, about

16,000 men

[=] so that the number previously estimated as a maximum
will be available

240,000 men

Whether financial considerations, domestic complications, or political reasons will possibly even preclude such a development of Austrian forces is a question that has to remain undecided here. The military calculus can only reckon with given magnitudes, with the normal figures of the war budget, and the efficiency of the means of transport. But the result depends not only on the size of the troop formations but also on the time within which these can be used by each side. And it is in this very respect, as just shown, that Bavaria’s behavior comes very substantially into consideration, while the possible armaments of the South Germans matter much less.


Source: Helmuth von Moltke, Moltkes militärische Werke, edited by the Great German General Staff. Berlin: Ernst Siegfried Mittler und Sohn, 1896–1912, vol. 1, pp. 74–76.

Translation: Jeremiah Riemer