Prussia did not cope well with independance. First of all, the morale of the Prussians became very low following defeat in the Austrian-Prussian War. Economic recession quickly followed, and Prussia became one of the poorest countries in Europe.
One of the most important causes of the 1881 Revolution was the rise of Polish nationalism. There were 2.4 million Poles in Prussia, constituting a sixth of the population, and they were treated at the time like second-class citizens. Although few German Prussians sympathised with them, they remained a powerful force in Prussia (albeit not politically) and many Prussian politicians attempted to promise them some autonomy in return for support. None of these promises, however, went far enough for the Poles.
The second cause was the frustration of many Prussians over the unfair political system, for instance, the three-class franchise system that gave those who paid more taxes a vote worth more than that of those who paid less.
Tension did not become visible unrest for some time due to the disunity of anti-government factions. However by 1881 the revolutionary Party of the Prussians had forged an agreement with Polish nationalists, and in that year revolts erupted throughout the kingdom. The 85-year old king Wilhelm I was exiled and the Republic of Prussia was born.
However the new government was even less democratic than the old and this angered Prussians, especially as the Poles, who had been granted autonomy in reward for their aid, were running their state democratically. Later that year the new government was toppled and for the first time Prussia had its first fair elections.