28th April

On this day in 1693, Leibniz wrote to de L'Hôpital, announcing his discovery of determinants fifty years before Cramer, who was the real driving force in the development of determinants. Leibniz's work had little or no influence because it was not published until 1850 in his Mathematische Schriften.

On this day in 2016 Google released an Ayrton doodle.