Why did Otto von Bismarck urge a moderate peace with Austria after the Seven Weeks’ War?

After the decisive Prussian victory at the Battle of Königgrätz in 1866, Otto von Bismarck urged a moderate peace with Austria for two primary reasons:

• Geopolitical Stability: Bismarck believed that maintaining a strong Austria was essential for the long-term stability of the European continent.1
• Risk of Foreign Intervention: He feared that if the war were prolonged, other powers—specifically Napoleon III of France—might intervene in German affairs to exploit the conflict.21

Against the wishes of the Prussian king and his generals, who desired to march on Vienna, Bismarck pushed for a quick cessation of hostilities. This approach, formalized in the Peace of Nikolsburg and the Treaty of Prague, ensured that Austria was not humiliated and retained its territories, with the exception of Venetia. By avoiding a harsh peace, Bismarck successfully secured Prussia's hegemony in Germany while preventing the potential for a wider, more dangerous international conflict.21