Elizabeth Mary Brittan, known as Mary Brittan, was born into an Anglican medical family in Castleton, near Sherborne, Dorset, England, on 30 March 1845. After her mother, Elizabeth Mary Chandler, died in 1849, her father, Dr Joseph Brittan, married his deceased wife's sister, Sophia Chandler, at Gretna Green, Scotland, in 1851. The scandal caused the family to sail to New Zealand. They arrived at Lyttelton on the William Hyde on 7 February 1852. Joseph Brittan lived on land speculation and small farming and helped start a newspaper, the Canterbury Standard, to oppose the planned Lyttelton tunnel.
The family lived at Linwood, beside the Avon River, in Christchurch. Mary sang in the choir of the cob church, Holy Trinity, nearby, and attended Mrs Thomson's School for Young Ladies from 1854 to 1861. Political discussions at home sparked a lifelong interest in politics in young Mary. As Sophia Brittan became an invalid, Mary had to keep house and act as hostess for her father, and developed a strong self-reliant character.
On 24 May 1865 Mary Brittan married William Rolleston at Holy Trinity Church, Avonside. Rolleston was a Cambridge graduate, then beginning his political career. They had four daughters and five sons. William was often away on provincial and parliamentary business so that Mary raised the children largely alone.
From 1865 to 1868 and from 1880 to 1884 the family lived with William Rolleston in Wellington. Mary Rolleston loved the political, social and cultural excitement of the capital. A brilliant hostess, she was charming, well groomed and politically astute. She was soon accepted in Wellington's élite circles and kept a salon attended by prominent men.
At first Mary Rolleston was William's political confidante, but this changed in later life as their political differences emerged. Mary's outlook was conservatively Victorian and her views frequently contradicted those of her more liberal husband. She considered the Maori to be a 'backward' race while William Rolleston, as native minister, attempted conciliatory negotiations with Te Whiti-o-Rongomai III at Parihaka, only abandoning his enlightened approach under duress. Mary's friends included some of the biggest landholders in Canterbury and she was embarrassed when William, as minister of lands, moved to make land available for small farmers. They both believed education was essential for all, but while William opposed religion in state schools, Mary campaigned vigorously for the Bible in schools cause. Influential herself, she had no wish to give political power to other women. She opposed women's suffrage, judging her sex unintelligent and inexperienced. Although she became a teetotaller, she did not assist the suffragettes' prohibition campaign.
As wife of Canterbury's provincial superintendent Mary Rolleston had enjoyed William's triumphs, but she also shared his political unpopularity. Financial difficulties in 1884 forced her to leave William in Wellington and live in the primitive house at their South Canterbury farm, Kapunatiki. She now baked bread, made candles and soap, sewed clothing, and managed the farm in order to free William for his career.
William Rolleston died at Kapunatiki on 8 February 1903. Afterwards, with the exception of two visits to England and moves to be with her son in Wellington during parliamentary sessions, Mary Rolleston lived in Christchurch. She was involved in church, choral, art and music societies. In the 1870s she had helped run a refuge for immigrant domestics and in the 1920s she was president of Canterbury's Women's Club and of the Women's Branch of the Citizens' Association. Mary Rolleston was constantly in demand at social functions. In 1900 Charles Bowen stated that her influence was not exerted in a noisy, obtrusive or officious manner and added that the public of New Zealand owed a deeper debt of gratitude than it could possibly hope to repay. As a talented and strong-willed wife of a leading nineteenth century politician, Mary Rolleston became a force in politics before women won the vote in New Zealand in 1893. She died in Christchurch on 4 June 1940 and was buried at Holy Trinity Church, Avonside.