March 15:
A.D. 351: Emperor Constantius II elevates his cousin Gallus to Caesar, giving him command of the Eastern Roman Empire.
A.D. 1493: Columbus returns to Spain after his first voyage.
A.D. 1545: The first meeting of the Ecumenical Council of Trent commences.
A.D. 1892: The escalator is patented by Jesse Reno of New York City.