vicissitude

noun

1. Regular change or succession from one thing to another, or one part of a cycle to the next; alternation; mutual succession; interchange; variability.
2. (in-plural, often)A change, especially in one's life or fortunes.

   “And God made.. the Stars, and set them in the firmament of Heaven to illuminate the Earth, and rule the day in their vicissitude...”

   “Among the vicissitudes incident to life, no event could have filled me with greater anxieties than that of which the notification was transmitted by your order, and received on the fourteenth day of the present month.”

   “The vicissitudes of war in Iraq cast a dreary backdrop for Donald Rumsfeld's first visit to Asian military allies since he became US Defense Secretary in 2001.”

   “Engaged intellectuals were obliged to take a stand on the side of progress and History, whatever the occasional moral vicissitudes.”

   “Despite all the monarchy’s vicissitudes, however, Queen Elizabeth II, a figure from another age, who was stiff and formal and not noticeably particularly warm and empathetic, had won and retained the affection, loyalty and support of the overwhelming majority of the British public, who respected her for her diligence and sense of duty.”