Profiting by the neglect of the Prussians, Napoleon seized upon the great defensive works of the country, which, to his great joy, were readily surrendered into his hands by the old and inefficient generals who commanded them; and French garrisons were almost immediately established in the fortresses of Stettin, Custrin, Glogau, Magdeburg, Spandau, Hameln, Nieubourg, &c.

"Spandau," said he in the 19th Bulletin, "is an inestimable acquisition.

In our hands it could sustain two months of operations.

But such was the general confusion, that the Prussians had not even armed its batteries." The possession of these fortifications inclined the scale at Eylau.

All the historians of the war notice their influence on the campaigns of Friedland and Tilsit.
These Prussian fortresses were retained by Napoleon at the treaty of Tilsit.