Eamon de Valera (1882-1975), Irish politician and patriot, prime minister (1932-48, 1951-54, 1957-59), and president (1959-73) of the Irish Free State, he was once a high school mathematics teacher. An active revolutionary from 1913, in the (doomed) anti-British Easter Rising on Easter Monday, April 24, 1916, in Dublin (1916), de Valera commanded an occupied building and was the last commander to surrender. Because of his American birth -- to a Spanish father, in New York City -- de Valera escaped execution by the British but was sentenced to penal servitude.

While in prison, de Valera reviewed some mathematics on the whitewashed walls of his cell. And he enscrawled the Fundamental Equation of Quaternions which he'd seen on a stone on Broome Bridge, outside Dublin, where Sir William Rowan Hamilton (1805-1865), scratched it in 1843.

The motivation was to celebrate a great accomplishment by an Irishman.

And de Valera might also have been proud that the University of Dublin was the only college who would accept the great British mathematician, George Boole (1815-1864), whose mathematics led to the logic circuits of our computers.