Cardano's famous book "Ars Magna" (1545) marked the end of the medieval period in mathematics and triggered the development of modern mathematical notation. The famous formula for the cubic, as presented in the "Ars Magna", resembles more a culinary recipe than a modern formula. The switchover has implications for the teaching of mathematics.
Andrew Gleason joined the Harvard faculty in 1950 and continued there until 1992 when he became Hollis Professor of Mathematicks and Natural Philosophy, Emeritus. He is best known for his work on Hilbert's fifth problem, measures on the closed subspaces of Hilbert space, and Banach algebras. He has been interested in mathematics education since 1959 when he chaired the advisory committee of the School Mathematics Study Group. He has spoken at several conferences on the teaching of calculus and is one of the members of the Calculus Consortium based at Harvard.