Alles mit Gott und nichts ohn' ihn, BWV 1127
Duke Wilhelm Ernst of Saxe-Weimar was born on 19 October 1662 (O.S.). He became co-ruler of Saxe-Weimar with his brother, Johan Ernst III in 1683. When Saxe-Weimar changed to using the Gregorian calendar, he chose 30 October to be his new birthday.