It’s October 16th, and on this day in 1843, the fundamental formula for quaternions was first written. Irish mathematician, Sir William Rowan Hamilton, while walking with his wife in Dublin, was struck by the formula that would revolutionize the study of dynamic systems. Excited, lacking paper, and not wanting to forget his stroke of genius– he carved the formula for quaternions into the stonework of Broome Bridge. Where it remains to this day.