Complex sentence: On November 9,1918, William II had abdicated and Germany was declared a Republic and on November 11,1918, the armistice between the warring factions of World War I was signed.
Split into simpler sentences: On November 9,1918, Wilhelm II had abdicated and Germany was declared a Republic. Two days later, on November 11,1918, the armistice between the belligerents of World War I was signed.