Simple past tense and past participle of happen. (verb)
Examples of word happened
I swore under my breath, because it had happened without me even realizing it'the only way it ever happened_ 'anymore.
I know I don’t know the truth about Andy or what happened, or why it happened but it happened.
There we were again, left without a keyboard player, and I started asking around until somebody told me that I should go see this band that had this great singer and piano player, and his name happened to be Isaac Hayes.
Perhaps their greatest moment on the title happened towards the end of the run, with the classic storyline that was so influential that it must have been homaged about three gazillion times since then - where Spider-Man is trapped under heavy rubble and is forced to fight against all odds to escape with the cure for Aunt May suffering one of her many illnesses.
"Whatever his title happened to be in the White House, I always knew that his real job was figuring out to make good policy good politics," Clinton said.