Power, Marguerite Agnes (1815?–1867), writer and traveller, was born in Ireland, daughter of a Col. Power. Her aunt was Marguerite Gardiner (née Power) (qv), countess of Blessington, and she later lived with her aunt at Gore House, Kensington, London, where the two women were well known in society and literary circles. In 1849 she went with her aunt to Paris when Lady Blessington moved there to live with the count d'Orsay, and she attended the countess when the latter was seized with a sudden and fatal illness. A talented and clever writer in her own right, she wrote a biographical sketch of her aunt, which was included in the preface to Lady Blessington's Country quarters (published 1850).
She wrote a considerable amount of poetry, and her poems were published in journals such as the Irish Metropolitan Magazine, Forget-me-not, and Once a Week. From 1851 to 1857 she edited the Keepsake. Her other publications included Evelyn Forester: a woman's story (London, 1856); The Foresters: a novel (2 vols, London, 1858); The letters of a betrothed (London, 1858), published under the pseudonym ‘Honoria’; Nelly Carew: a novel (2 vols, London, 1859); Virginia's hand (London, 1860); and Sweethearts and wives (3 vols, London, 1861). Her works were highly acclaimed in her day, Evelyn Forester being described as ‘unquestionably altogether superior to any work of fiction that proceeded from Lady Blessington's pen' (Allibone). Yet despite this, her works have been largely forgotten.
She also travelled widely, and in 1862 visited Egypt, where she stayed for a winter in Alexandria, lodging with her friends Henry and Janet Ross. She later published an account of this expedition, Arabian days and nights, or rays from the East (London, 1863), dedicating the book to the Rosses. After a long illness, she died in London in July 1867. Some of her work later appeared in the anthology compiled by Stopford Augustus Brooke (qv) and T. W. Rolleston (qv), A treasury of Irish poetry in the English tongue (London, 1900).