The historian Lord Bullock, author of what is widely regarded as the definitive biography of Adolf Hitler, died in a an Oxfordshire nursing home yesterday at the age of 89.

The founder of St Catherine's College, Oxford, he was hailed as an intellectual giant, but also as one of the country's most engaging and admired public figures in the latter half of the 20th century.

The only child of a gardener - who later became a Unitarian minister - and a domestic maid, Alan Bullock grew up in the Avon valley near Bath, then, after the family moved north, attended Bradford grammar school.

He won a classical scholarship to Wadham College, Oxford, where he took a first in Greats in 1936 and a first in modern history two years later.

He worked briefly for Winston Churchill, on his History of the English-Speaking Peoples.

When war broke out he was declared unfit to serve in the armed forces because of his severe asthma, and he joined the European Service of the BBC, eventually becoming the corporation's diplomatic correspondent.

After the war he was elected fellow and tutor in history at New College, Oxford, where, crucially, he influenced an entire generation of undergraduates who had returned from active service.

Asked by the publishers Odhams to write the first biography of Hitler, he produced Hitler: a Study in Tyranny, which was published in 1952 and soon became the standard text on the German dictator.

Other biographies have appeared since then, but Bullock's famous maxim "Hitler was jobbed into power by backstairs intrigue" has stood the test of time after being drilled into thousands of students of Weimar and Nazi history.

Without doubt one of his most remarkable and formidable achievements was his founding of St Catherine's, created from the all-male St Catherine's Society as a college dedicated to the study of arts and science. Between 1958 and 1964 he drummed up the equivalent of £32m in today's money from businesses and charitable foundations.

The current master of St Catherine's, Roger Ainsworth, said: "Lord Bullock's energy and vision were renowned for stimulating academics and students alike. The pre-eminence of his academic writing and his creative dynamism, which led to the founding of St Catherine's, provide an enduring legacy."