December 12, 1918 
LAND &? WATER 
The Bridge-heads of the Rhine : By Hilaire Belloc 
In this article Mr. Belloc discusses the meaning of the term "bridge-head" in strategy, and 
analyses the particular character of the three bridge-heads to be occupied by the Allies under the 
terms of the armistice. The meaning of the Rhine crossings at Cologne, Coblentz, and Mayence 
(the three bridge-heads which are to be held by the British, American, and French respectively) is 
explained, and the geographical origin and present functions of each is touched upon and illustrated. 
THE terms of armistice have for their chief geo- 
graphical demand the occupation of all the 
country on the left of the Rhine, the evacuation 
by all German armed units of a belt twelve miles 
broad on the right bank of the Rhine and, further, 
the occupation by the Allies of three bridge-heads, to wit — 
Cologne, Coblehz, and Mayence. 
What is the significance of this last clause ? 
Why does Marshal Foch insist upon the occupation of 
these bridge-heads ? 
What is the meaning of a bridge-head ? What is the 
military effect of holding one, and why are these three bridge- 
heads of such peculiar importance ? 
Nature and the works of man present to the advance of 
armies a number of obstacles — that is, types of ground 
across which it is difficult for an army to advance : or, to 
make the definition more accurate, "types of ground" the 
advance of an army over which must necessarily be slower 
than it is over the average of ground. 
Ground of this sort, called an "obstacle" in mihtary 
historj', has the following effect in the conduct of armies ; — 
(i) It provides a shelter or screen behind which a defeated 
force may have time to rally, or an advancing force have 
time to concentrate. 
(2) It normally confines an advance across it to what are 
called defiles — that is, narrow passages during the course of 
which an armed body is difficult to use, it being drawn up 
in column and unable to fight save with its most advanced 
units, which are, of course, a very small proportion of the 
whole. ~ 
(3) The converse of this last : an obstacle being present 
behind a large force which has suffered defeat, that obstacle 
will interfere with rapidity of retreat, and therefore assist 
to turn retirement into disaster. 
It is with the second of these three characters that we 
are here concerned. 
The three great types of obstacle generally present in 
military history are a marsh, a river, and' a chain of moun- 
tains One has also to consider on particular occasions the 
desert and the sea, but it is rarely that these are on such a scale 
that they can be truly called "obstacles." They are not 
usually present save in the case of very narrow patches of 
desert or narrow arms of the sea. 
MARSH, RIVER, AND MOUNTAIN 
Of the three common types of obstacle — marsh, river, and 
mountain — marsh is by far the most serious. On the other 
hand, the presence of marsh extended over a wide space of 
country and in a lengthy belt is very rare. Further, it is 
not usual to find marsh wherever it exists on a large 
scale separating the regions in which armies are likely to 
ojjerate. There are, indeed, exceptional cases, one of the 
most interesting of which is the case of the Mersey Valley 
between the Pennine Hills of North England and the Irish 
Sea. It was the marshy ground between Stockport and the 
Wirral peninsula which cut off Lancashire from the rest of 
"England, and which determined the Roman mihtary plan of 
that region. The main Roman road to the north was forced 
to creep between the hills and the marshes near Stockport, 
and this gap was defended by the fort which was the origin 
of Manchester. The main belt of, marsh was crossed by two 
roads. One struck right across the centre to Warrington, so 
that a post established there could be at one long day's 
march from the shipping at the mouth of the Mersey on the 
one hand, and the fort of Manchester on the other. The 
second road struck north-eastwards towards Manchester - 
across the marsh, and these two causeways have left their 
record on the place-names of the district under the titles 
of Stretford and Stretton. 
Only by the defile of Stockport could armies from the 
south come up to Lancashire north of the Mersey, and all 
through English history, right down to the Civil Wars, you 
wilL find those three roads — the three crossing-places of the 
marshes — playing their part, and Manchester and Warrington 
acting as the hinges of the local campaign. 
But marsh, I say, is a rare kind of obstacle, at any rate as 
separating two regions where armies are likely to manoeuvre. 
Much the commonest sorts are the river and the mountain 
chain. 
Both these two kinds of obstacles have it in common 
that an army to march with ease across them must in practice 
take advantage of comparatively few avenues. In mountains 
these avenues are the passes, especially those provided with 
roads, and their importance increases with the ruggedness 
and impassable character of the hills upon either side of 
each pass. Thus, one may say that in the Alps the move- 
ment of armies is entirely confined to a few passes. To a 
lesser extent this is also true of the Pyrenees, but it is generally 
V f -f ^ ^ -V ^ f 39 7i^/>.-: 
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true of all hills, even of those which have not the impassable 
character of high mountains. For even where you are deal- 
ing with open rolling hills of no great height — the Pennines, 
for example — any force which you try to advance off the main 
roads in the passes would move so slowly compared with those 
using the main roads and passes that cither the whole army 
would be compelled to an extremely slow advance, giving 
every advantage to its opponent (for one of the chief factors 
of advantage in war is speed), or you would have portions 
of your army moving far more rapidly than the rest and there- 
fore a disintegration of forces. In practice, then, armies, 
in dealing with the obstacle of ranges of mountains or of great 
hills, must use the main passes and the roads accompanying 
them. The problem has been slightly modified in modem 
