156 THE SEVEN YEARS WAR, 1756-63
the rest of the war. With his Hanoverians and his other Protestant
German troops, Ferdinand launched a lively offensive in February
and early March 1758, and succeeded in turning the French out of
Hanover and Brunswick and forcing them to retire across the Weser.
Ferdinand ultimately took 100,000 British and Germans under his
command, and in spite of every vicissitude of fortune he maintained a
successful defence of Hanover and kept the French at a good arm's
length from the vital fortress of Magdeburg, which supported the
Prussian effort in Saxony.
Prince August Wilhelm was near death, and had been rejected by
Frederick for high command. As some compensation, the next in line
of the royal brothers, the thirty-two-year-old Henry, began to impress
himself on Frederick as a clear-headed and expert, if also notably
cautious, officer, very well suited for detached commands on the
main theatre of war. We will often see Henry posted in Saxony or on
the Oder, holding the enemy clear of Frederick's flanks and rear,
while our hero dashes hither and thither intent on carrying out some
great stroke with the royal army.
Frederick was certain that the main business of 1758 must be to
throw back the Russians, who overran East Prussia in January, and
who were sure to advance against the Oder. In order to have his hands
free to deal with the Muscovites, Frederick intended to take the field
very early and paralyse the Austrians by a grand strategic diversion.
This was to take the form of an offensive from Upper Silesia into
Moravia, where a siege of Olmiitz would open many interesting
possibilities. Olmiitz lay on the direct path to Vienna, and the
Austrians were certain to respond in a dramatic fashion. Perhaps they
might offer battle under circumstances favourable to Frederick. At
the very least they would pour forces into a theatre of war where they
could be of no conceivable use to the Russians.
On 17 March 1758 Frederick planted his headquarters in the
monastery of Griissau, which lay in a small plain in Silesia, beset with
pine-covered hills on all sides. From here he could follow the progress
of the siege of nearby Schweidnitz, and supervise the gradual assem-
bly of his troops and transport train at Neisse. Frederick encouraged
the belief that the thousands of waggons were being gathered in order
to convey the magazine at Neisse westwards to Glatz, and thus open
the way for an offensive into Bohemia.
The Prussians normally did not excel in the siege of fortresses, but
on 18 April Frederick abridged the operation against Schweidnitz by
launching a dangerous but successful storming of the Galgen-Fort.
The commandant of the whole fortress-complex at once surrendered.
This agreeable postscript to the campaign of 1757 delivered nearly
5,000 men into Frederick's power and gave him great quantities of