What is the oldest accurately datable event in history?

I've just been wondering to myself - what is the oldest, verifiable date in history?

I hope my wording is clear, but just in case, what I am asking is what is the oldest event in history that we can be certain happened on a specific date?

Does anyone know? And if so, how can we be so sure of the date?
Update: Wow Aj, that was quick! Thanks matey!
Update 2: Three great answers already... and three different interpretations of what I tried to say! Thanks guys. WHat I meant when I asked the question was what is the verifiable date i.e March 19th 1234BC, for example. But the Battle of Qadesh answer is equally interesting - the date is only known approximately, but the... show more Three great answers already... and three different interpretations of what I tried to say! Thanks guys.

WHat I meant when I asked the question was what is the verifiable date i.e March 19th 1234BC, for example. But the Battle of Qadesh answer is equally interesting - the date is only known approximately, but the event is a true historical event, as opposed to a myth. I'm interested in both set of answers please.

The other answerer (sorry - can't see your name as I type) referring to geological periods is not really what I meant to ask about. It's really historical events I am interested in - battles, deaths of ancient rulers, solar eclipses maybe, maybe sightings of comets.

But keep the answers coming please - this is fascinating stuff! Thanks everyone who answers.
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