happened

Concise Oxford English Dictionary © 2008 Oxford University Press:
happen/ˈhapən/

▶verb

• 1 take place; occur.

• 2 come about by chance.

  ■ chance to do something or come about.

  ■ (happen on) come across by chance.

  ■ used as a polite formula in questions: do you happen to know who her doctor is?

• 3 (happen to) be experienced by; befall.

  ■ become of.

▶adverb N. English perhaps; maybe.

– phrases
as it happens actually; as a matter of fact.

– origin ME (superseding the verb hap): from the noun hap + -en1.