The black death. If you're talking about Europe.
Here is your answer
The Prussian state power dominated the nation building process in Germany. The key role was played by Otto von Bismarck, its chief minister with the help of Prussian army.
There were three wars over 7 years with Denmark, Austria Hungary and France between 1864 and 1871 which ended in Prussian victory.
HOPE IT IS USEFUL
An amendment or ratification to the constitution.
