My fanon: Trying to calculate a more efficient method of moving the sun and moon, so it will only burn out the magic of four Unicorns each time rather than five. Sadly he was unsuccessful, but his efforts were so through that a later scholar’s deep analysis of them would result in the discovery of a new mathmatical theorem with widespread application.
When told of this in the modern era he got slightly misty eyed and said “Well… it is something at least.”
Edited because: Everything after 1st sentence.