Hatton was both distinguished and influential as a scholar, and memorable as a personality. Striking in appearance with a distinctive mane of blonde hair, she was a notably successful woman academic when that was even less common than it is today. Her formidable energy, effervescent personality, celebrated generosity to fellow scholars, dry sense of humour and immense charm gave her a wide circle of friends in Britain and overseas.
Born Ragnhild Hanssen in the Norwegian port of Bergen, she came to Britain in 1936 to begin her postgraduate education at University College London. Her marriage in that same year to Harry Hatton, which was to be an especially close partnership, ensured that Britain became her homeland. Yet though this brought British citizenship, her assimilation was far from complete. She always remained an exotic species within the staid corridors of British academic life. Even her name could occasionally be a source of misunderstanding. She liked to recall how for some years she was on the electoral register as "Reginald Hatton" and how it took the evidence of two sons to convince the authorities that she was not a man.
The progress of her postgraduate research was slowed by government service during the Second World War and by the birth of her children. Like many of her contemporaries, this wartime experience contributed significantly to her subsequent career. It confirmed her interest in the making of policy at the highest level, and also persuaded her of the crucial distance which often separated intention from achievement, in the past as in the present: these were to be two recurring themes in her writings.
After 1945 she resumed her studies and became an Assistant Lecturer at the London School of Economics in 1949. Her Norwegian background always remained important in her outlook: it gave her a command of all the main continental languages and of several minor ones as well. More importantly, it provided the sense of Europe as a political and cultural community which lay at the very heart of her scholarship, together with a remarkable freedom from nationalistic prejudices. Her seminal studies of Louis XIV's foreign policy, for example, were notable for her ability to discard the stereotypes of earlier patriotic historiography, both pro-French and anti- French.
Her publications covered an unusually wide geographical area, and extended from political subjects into the developing field of the history of courts and of monarchical culture. A detailed study of European diplomacy during the second decade of the 18th century, Diplomatic Relations between Great Britain and the Dutch Republic 1714-21 (1950), was followed by a celebrated political biography, Charles XII of Sweden (1968), surprisingly the first scholarly life of that remarkable monarch in any language. There was also a series of influential studies of Louis XIV (published in four volumes, 1969-72), concentrating especially on his foreign policy and his court at Versailles. Her final important work was an acclaimed biography, George I: Elector and King (1978), unusual in that it viewed him as ruler of Hanover as well as of Britain. She edited several scholarly volumes and contributed to many more.
Hatton's energy and enthusiasm were legendary: even in retirement she continued to travel frequently to archives in Europe. Her capacity for hard work could be intimidating: she once half-complained, after a trip to Stockholm, that she had not seen any Strindberg on that particular visit because Swedish archives remained open in the evenings. It was characteristic, however, that she saw this as an omission to be regretted. She had wide cultural interests and an especial love of music, while her happiest times were either travelling with her husband in Europe and in the United States, or sailing with him from the family cottage at Paglesham, in Essex.
Ragnhild Hatton's academic honours came at a relatively advanced stage in her career: her most important books appeared from the late 1960s onwards, a tribute to the extensive research upon which they were based and also to the crucial importance she always attached to family life. She taught at the London School of Economics for over three decades, rising to be Professor of International History there and doing much to shape the discipline and the department, rightly regarded as the foremost centre in Britain for the subject. She was a renowned supervisor of graduate students: demanding and expecting the same high standards which she set herself, but at the same time remarkably conscientious, caring and supportive. Many of the men and women who studied with her went on to successful careers outside as well as inside the walls of academe, and all continued to acknowledge their debt to her. In her life as in her historical scholarship, people were all-important.
Her influence extended far beyond London University: she created and maintained close links with historians throughout Europe and in the United States, and did much through her Seminar at the Institute of Historical Research and through personal contacts, to bring scholars of all nationalities together. Her books were widely translated, and this, together with the Norwegian, Swedish and French honours bestowed upon her, was an especial source of pride: she was even more highly esteemed outside Britain than within. After her retirement in 1980, her husband's illness and eventual death slowed her own scholarly output: it was entirely in character that she unhesitatingly put his welfare first. Her own failing health clouded her final years. Yet she retained a lively interest in her subject and in her friends and pupils, and could always enchant by her lively intelligence, compassion and love of life.
Ragnhild Marie Hanssen, historian: born Bergen 10 February 1913; Assistant Lecturer, Lecturer, Reader and Professor of International History, London School of Economics 1949-80 (Emeritus), Dean of the Faculty of Social Sciences 1974-78; Fellow, Swedish Vitterhetsakademi 1954; Foreign Member, American Historical Association 1979; Senior Fellow, British Academy 1993; married 1936 Harry Hatton (died 1989; two sons); died London 16 May 1995.