Here we are. My OC Stand-In.
I tried to keep him as Non-Marty Stu as possible.
Canterlot Librarian and Historian, Purple Patch.
Growing up in Canterlot around the same time as Twilight Sparkle became Celestia' apprentice, Purple Patch got along well with the young unicorn.
Her precocious little dragon, however, was more of a handful. Spike's forgetfulness could often land him, or others, in quite the predicament.
Working at the Grand Academy (Which Princess Celestia's School For Gifted Unicorns is a prominent branch of), Purple Patch sometimes works as a lecturer in the finer points of Equestrian and world history.
Twilight Sparkle and Moondancer were probably the only ones that managed to stay awake during his lectures.
Purple's life's work is the unravelling of Equestria's deeper histories, buried long ago and hidden away in cryptic runes and passages that only highly advanced practices of all magics can uncover.
Working with his Farman friend, Wagensroll, and his cervine colleague, Dawnwind the Seer, they combine various lofty arts to unravel things previously thought lost to time.
The three historians worked chiefly in creating a system of contraptions that allows projections of the past to materialise in the modern day to better research and document details of history.
A small side-affect is that it's not fussy about what it shows and can often portray events best not put to paper such as the private lives of famous figures of history.
It seems ponies in those days weren't quite as modest as previously thought.