Complex sentence: On 11 November 1918, Emperor Charles I of Austria relinquished power and, on 12 November, the ethnic German areas of the empire were declared the Republic of German Austria with the intent of unifying with Germany.
Split into simpler sentences: On 11 November 1918, Emperor Charles I of Austria relinquished power. On 12 November, the ethnic German areas of the collapsing Austrian Empire declared themselves the Republic of German Austria, intending to unite with Germany.