Professor Mark David Bailey (born 21 November 1960, Castleford, Yorkshire) is the High Master of St Paul's School, London and professor of Later Medieval History in the University of East Anglia. He was previously an England rugby footballer and toured South Africa during the Apartheid era in 1984.
Bailey was educated at Ipswich School (1972–79) and at the College of St Hild and St Bede University of Durham (1979–82), where he obtained a first-class degree in Economic history. He went on to study for a PhD in History at the University of Cambridge, which was awarded in 1987.
He won the Cricket Society's Wetherell Award in 1979 for the best public school all-rounder and played for the NCA Young Cricketers in 1980. The same year he made his debut in the Minor Counties for Suffolk, for whom he played until 1991 and served as captain between 1988–90.
Bailey played rugby for Durham University and Cambridge University, captaining the latter in the 1983 and 1984 Varsity matches. He won four Blues at Cambridge. He later served as Secretary of CRUFC, as its representative on the Rugby Football Union, and since 2010 has been President of the club. Bailey played on the wing for Bedford in 1981–2 and for London Wasps between 1984–90, winning the premiership in the 1989–90 season. He also received international honours for England, capped seven times, and played for the Barbarians invitational side. On 16 June 2003, Bailey was honoured with Durham University's Palatinate Award for Sport.
Bailey was a Fellow of Gonville and Caius College, Cambridge, between 1986 and 1996, lecturing in history and working as Admissions’ Tutor. He left Caius to become a Fellow of Corpus Christi College, Cambridge as Praelector in History and Domus Bursar (1996–99). In 1999 he was appointed Head of Leeds Grammar School, despite some opposition from the local teachers' union. He led the merger of Leeds Grammar School and Leeds Girls' High School in 2008, following his earlier appointment (2005) as both Headmaster and Chief Executive of the Grammar School at Leeds.
In 2010 Bailey left Leeds to spend one term as a Visiting Fellow in Medieval History at All Souls College, Oxford. He then took up the post of Professor of Later Medieval History at the University of East Anglia. In 2011 he succeeded George Martin Stephen as High Master of St Paul's School, London. He remains a Visiting Professor at UEA.
Bailey has been invited to deliver the Ford Lectures in British History at the University of Oxford in 2019. He has written seven books and published a number of academic articles on the economy and society of medieval England. His most recent book is The Decline of Serfdom in late medieval England: from bondage to freedom.