Conversation so far:
What foreign affairs was Wilhelm II, German Emperor involved in?
Wilhelm II, German Emperor invented and spread fears of a yellow peril trying to interest other European rulers in the perils they faced by invading China.
When did Wilhelm II, German Emperor gain the position of German Emperor?
Wilhelm II, German Emperor reigned from 15 June 1888 until his abdication on 9 November 1918 shortly before Germany's defeat in World War I.
Is there anything important I should know about Wilhelm II, German Emperor?
A domestic triumph for Wilhelm II, German Emperor was when his daughter Victoria Louise married the Duke of Brunswick in 1913.
Did Wilhelm II, German Emperor accept his daughter's marriage?
Princess Victoria Louise of Prussia's marriage to the Duke of Brunswick helped heal the rift between the House of Hanover and the House of Hohenzollern.

Question: Why was there a rift between Hanover and Hohenzollern?
Self-contained rewrite: Why was there a rift between the House of Hanover and the House of Hohenzollern?