Carola Mary Anima Oman was born on 11 May 1897 in
Oxford, the second of three children of the military historian Sir
Charles Oman (1860–1946) of
All Souls and his wife Mary (1866–1950), daughter of General
Robert Maclagan of the
Royal Engineers. She described her upbringing in her final book, illustrated with photographs:
An Oxford Childhood. As a child, Oman wrote several plays that were performed by friends. Another early interest was photography. She was sent in 1906 to Miss Batty's, later
Wychwood School in
Oxford. She would have liked to have gone to boarding school, but her parents would not agree, and she continued at Miss Batty's until the spring of 1914. The family moved in 1908 into
Frewin Hall, now part of
Brasenose College, Oxford. Her brother Charles (C. C. Oman) became a keeper of the
Victoria and Albert Museum and wrote several books on silverware and other domestic metalwork. The set designer
Julia Trevelyan Oman (1930–2003) was her niece. Oman worked as a
VAD in England and then in France in 1918–1919: soon after her 1919 discharge, she met Gerald Foy Ray Lenanton (1896–1952), a soldier returning from France who would later join his family business as a timber broker. After marrying Lenanton on 26 April 1922, Oman became Lady Lenanton when her husband was knighted in 1946 for his World War II service as director of home timber production. The couple, who remained childless, lived from 1928 at Bride Hall, a
Jacobean mansion in
Ayot St Lawrence, Hertfordshire. In 1965, Oman produced
Ayot Rectory – A Family Memoir, about the Sneade family, who had lived in the village from 1780 to 1858. Oman was quoted as speaking warmly of fellow villager
George Bernard Shaw, who had been the Lenantons' first caller at Bride Hall in 1928. The novelist
Georgette Heyer was a lifelong friend, who compiled a 16-page index for Oman's
Britain against Napoleon, published in 1942 by
Faber. Another writer friend in Oxford was
Joanna Cannan, who dedicated her 1931 novel
High Table to Oman. ==Writings==