Bringing my post over from your thread in General:
Original message details are unavailable. Unfortunately, as far as I know, if the information is no longer on your Adventurer's Log/RuneMetrics, then there is no way to look up this data. Based on an external website that tracks experience, it appears you got it sometime this year between January and April, but I can't say what day for sure. Sorry.
Just so you know for the future, typically it is best to only create one thread, rather than multiple threads in multiple sections as this can cause a bit of spam.
"The man who acquires the ability to take full possession of his own mind
may take possession of anything else to which he is justly entitled."