Historian Professor Norman Cohn, who died on 31 July aged 92, was best known for The Pursuit of the Millennium: Revolutionary millenarians and mystical anarchists of the Middle Ages, published in 1957.
In 1963 he became a professorial fellow at Sussex and director of the University's Columbus Centre for studies of persecution and genocide. At Sussex he researched and wrote Warrant For Genocide (1967), which examined one of the most important sources of Nazi anti-Semitism, the forged document known as 'The Protocols of the Learned Elders of Zion'.
From 1973 to 1980 Cohn was Astor-Wolfson Professor of History at Sussex, then emeritus professor.
Dr Richard Lewis, Emeritus Lecturer in Mathematics, was a lecturer at Sussex from 1966 to 2003; he died on 26 July from lung cancer soon after his 65th birthday.
He was a talented mathematician and a willing colleague. Richard enjoyed all aspects of mathematics and communicated this to the students in the many different courses that he taught. He was a popular supervisor for student essays on mathematical games and played the game Go to a respectable standard.
Unusually for a mathematician, he changed his area of research; in his case, it was from algebraic topology to number theory, both fields of pure mathematics prominent in current mathematical activity. Richard completed a DPhil at Sussex in 1991.
His published output was distinguished by its elegance, even among the generality of papers in his field, where such a quality is often noted. Richard continued to publish up to and beyond his early retirement, his last papers appearing in 2003 and 2004.
James Hirschfield, Professor of Mathematics