Anzio
The active prosecution of the Italian campaign was entrusted to the 15th Army Group under the command of General Sir Harold Alexander. This formation consisted of two armies: the British Eighth under General Montgomery, and the newly formed American Fifth, commanded by General Mark W. Clark. The composition of the Eighth Army remained for the time being entirely British: the Fifth, though under American command, initially consisted of three American and three British divisions, organized in two corps.
The invasion was carried out in two phases. On September 3 the Eighth Army crossed the three miles of the Straits of Messina and landed on the Toe of Italy. On September 9 the Fifth Army made an assault landing at two points of the Gulf of Salerno. The Eighth Army's task proved unexpectedly easy. There was no opposition to the landing. The Germans had withdrawn some days before. The Italian soldiers who met the Eighth on the beaches cheerfully assisted with the disembarkation. The subsequent advance up the southernmost two hundred miles of the country was nothing more than an exercise in organization and rapid movement. For the Fifth Army it was another matter.
The Italian armistice was signed, as we have seen, a few hours after Montgomery's men landed. It was left to General Eisenhower to announce it at the moment he thought it would be most helpful to the invasion. He made the announcement, and broadcast a proclamation to the Italian people, on the night of September 8, as General Mark Clark's invasion fleet lay in readiness off the Gulf of Salerno. In the early hours of the following morning the British and American corps of Fifth Army simultaneously stormed the beaches at two points near Salerno, and immediately ran into the heaviest opposition.
Fred Majdalany. The Prologue. The Battle of Cassino. New York: Ballentine. 1957.
Meanwhile, by concentrating on resisting the Fifth Army landing, the Germans had left the Adriatic side of the country wide open. General Alexander was able to take advantage of this by ordering the Eighth Army to land its reserve divisions and open up an east coast front that would relieve the pressure on the Fifth Army, while the original Eighth Army landing force caught up with the Fifth and consolidated its advance in the center. Taranto and Bari on the east side were quickly occupied and the 78th Division of Eighth Army raced ahead to capture Foggia, whose dozen or so airfields were one of the major objectives of the campaign. Foggia was occupied on the 27th, as the Fifth Army prepared for the final stages of its attack on Naples. On October 1 the King's Dragoon Guards entered that city, and four days later the Eighth Army took Termoli on the east coast. With both terminals of the Naples-Termoli road---the only major lateral highway in southern Italy---firmly held, and Foggia and its airfields occupied, the Allied armies had in baseball parlance reached first base. It was to be many months before they made second base---the next important lateral between Rome and Pescara.
Fred Majdalany. The Prologue. The Battle of Cassino. New York: Ballentine. 1957.
One hundred and forty miles north of Taranto the broken land begins. Thereafter, for many miles along the Adriatic, rolling ridges and valley bottoms succeed in monotonous procession. Where spurs from the central mountain spine approach the coast, the ridges are sharper and more irregular, the valleys narrower and more abrupt. Twenty miles west of the mouth of the river Sangro, the Maiella massif abuts into the lowlands; the countryside between the sea and the mountains increases in ruggedness. The ridges are high, hog-backed, and even razor-backed; the water-courses are deep-cut and steep-banked. The roads are of secondary class, and usually traverse the crests of the ridges, in exposed positions. The countryside is intensively cultivated, even steep rocky hillsides being terraced for garden, patches and vines; the ditches and terrace walls are lined with pollarded willows and larches. On stony and sparse ground unfit for cultivation, thick clumps of scrub and bramble grow. The tightly clustered houses of the villages stand on the crests of the higher ridges. These hamlets offered excellent observation points, and afforded cover for men and guns.
It was in such countryside that the enemy elected to make his first stand. A flexible defensive zone had been created, which the Germans called the Gustav Line. Its positions began on the Adriatic coast near the mouth of the Sangro river, south of the port of Pescara. The zone traversed the valley of the Sangro, to the southern slopes of Monte Greto. Thereafter the fortifications followed the line of the Volturno Valley through Central Italy, thence through the Mignano Gap to Monte Camino, and on down to the Tyrrhenian coast.
The Blitzkrieg consisted in just this. Overwhelming forces were secretly concentrated opposite one small section of the opposing line---preferably a sector discovered by reconnaissance to be weak. A breakthrough was achieved. Armored forces were then poured through the gap, and wheeling left and right would swiftly fall upon the rear areas of those parts of the line that had not been attacked, thus throwing the whole defensive system into confusion. This was how the German army achieved its early victories, and how the "impregnable" Maginot Line was disposed of in a few days during the summer of 1940.
But the key to this pattern of attack is maneuverability. In order to build up local superiority of three to one and make the overwhelming thrust at the chosen point, the attacking army must have the power to maneuver swiftly and secretly so that the enemy is taken by surprise. The geography of Italy is such that even in dry weather power of maneuver is severely restricted, but between November and April it is nonexistent.
These two correlated tactical factors---the geography of the country and the consequent absence of the power of maneuver---are at the very root of what happened in Italy. All failures and all successes were directly related to them. And, coupled with the additional handicap of America's strategic reluctance to throw its full weight into the campaign, they produced as their logical outcome the long and costly battle of Cassino.
Fred Majdalany. The Prologue. The Battle of Cassino. New York: Ballentine. 1957.