There were two parties among the Poles; the one, the extreme Republican, wished for the institution of an independent republic; the other would be content with self-government and national institutions under the Russian Crown; they were supported by a considerable party in Russia itself.

Either party if successful would not be content with Russian Poland; they would demand Posen, they would never rest until they had gained again the coast of the Baltic and deprived Prussia of her eastern provinces.

The danger to Prussia would be greatest, as Bismarck well knew, if the Poles became reconciled to the Russians; an independent republic on their eastern frontier would have been dangerous, but Polish aspirations supported by the Panslavonic party and the Russian army would have been fatal.

Russia and Poland might be reconciled, Prussia and Poland never can be.

Prussia therefore was obliged to separate itself from the other Powers; instead of sending remonstrances to the Czar, the King wrote an autograph letter proposing that the two Governments should take common steps to meet the common danger; General von Alvensleben, who took the letter, at once concluded a convention in which it was agreed that Prussian and Russian troops should be allowed to cross the frontier in pursuit of the insurgents; at the same time two of the Prussian army corps were mobilised and drawn up along the Polish frontier.
The convention soon became known and it is easy to imagine the indignation with which the Prussian people and the House of Representatives heard of what their Government had done.