Early female and feminist art historian; translator of early and important German art histories into English. Rigby was the daughter of Edward Rigby (1747-1821), gynecologist and amateur classical scholar, and Anne Palgrave (Rigby) (1777-1872). She was privately educated in the arts and sciences as her well-connected and cultured parents determined. Her father died when she was twelve and thereafter she determined her education more personally. While living in Switzerland in 1827, taking a cure for typhoid fever, she learned German, translating the essay on English art collections by Johann David Passavant, Kunstreise durch England und Belgien, 1833. In 1836 work was published as Tour of a German Artist in England. She returned to London in 1832 studying art at the British Museum and the National Gallery in hopes of becoming a painter. Her first documented article was published in the Quarterly Review in 1842, writing regularly for it thereafter. She became close friends with John Murray III (1808-1892), the publisher of many art monographs, and his family. Through Murray, she met the painter J. M. W. Turner and literati. Rigby, a striking 5' 11" beauty, came to be known as a noted conversationalist. During an 1846 visit to the Royal Academy exhibition, she met the artist and then Keeper (curator) of the National Gallery, Charles Lock Eastlake. More travel to the continent, including an 1848 meeting with Passavant in Frankfurt, ensued. She continued writing reviews for the Quarterly Review. At age 40, she married Eastlake in Edinburgh in 1849, who had resigned from the National Gallery. Now Lady Eastlake, she moved to London to live with him. Her husband was knighted in 1850 and their only child stillborn the following year. The Eastlakes continued as fixtures in London intellectual circles: the historian Thomas Babington Macaulay (1800-1859), Charles Dickens (1812-1870), and Thomas Carlyle (1795-1881) among others. In the early1850s their formal dinners included Passavant and director of the Berlin Royal Gallery, Gustav Friedrich Waagen, both of whom stayed with the Eastlakes. In 1854 Lady Eastlake sided with Euphemia Chalmers Gray (1828-1897), the wife of John Ruskin, in her move to annul her married to Ruskin. Ruskin had been no friend to either of the Eastlakes, being partially to blame in her husband's resignation from the National Gallery. Beginning in 1852, the Eastlakes included Italy in their European excursions, which broadened Lady Eastlake's art-historical knowledge. In 1855 her husband was appointed first Director of the National Gallery; Lady Eastlake appears from that point to have been involved with purchase decisions for the Gallery. She translated anonymously the first volume of Handbuch der Geschichte der Malerei seit Constantin dem Grossen as Handbook of the History of Painting, The Italian Schools, the second edition of by Franz Kugler, in 1851, a work her husband had translated originally in 1842. The following year she began translating Waagen's evaluation of English collections, which appeared beginning in 1854 as Treasures of Art in Great Britain. When Anna Jameson, the early and important woman art historian died in 1860, Lady Eastlake consented to complete Jameson's History of Our Lord, a study of the iconography of Christ. Jameson's early proto-feminist art history appeared in 1864 completely due to Lady Eastlake. Her Quarterly Review contributions of 1850s and early 1860s, included a review of the Crystal Palace. Her sensitive article on photography (April 1857) was an accurate summary the history of photography and its relationship to art (Mitchell). In 1865, during their annual visit to Italy, Charles died in Pisa. In her widowhood, she developed a closer circle of friends, particularly with the archaeologist and National Gallery Trustee Austen Henry Layard. Through Layard's urging, Eastlake penned a memoir of her husband, published in 1870. Eastlake retained her interest in art history. In 1871 visited the famous Holbein exhibition in Dresden and trips to Venice in 1877, the Baltic provinces and St. Petersburg in 1878. In1883 she toured the Rossetti exhibition in London (describing it as "horrors, without a single merit"). In 1868 she co-wrote a piece with Harriet Grote espousing reform of the British Museum for the Quarterly Review. Her art historical work, on Leonardo da Vinci, Michelangelo, Titian, and Raphael, appeared mainly in the Edinburgh Review in the 1870s and early 1880s. She published her collected essays in 1883 as Five Great Painters. A new edition of her Handbook of Italian Art translation of Kugler also appeared. She died after declining health at her London home in 1893. She is buried in Kensal Green cemetery. Eastlake was a pioneer woman art writer, like several other women of her generation, Maria Callcott, Emilia Francis Strong Dilke, and Julia Cartwright.
At her best, her writing was an antidote to Ruskin's literary and Romantic approach to art. Her early and complete knowledge of continental art historians such as Joseph Archer Crowe, G. B. Cavalcaselle, and Giovanni Morelli gave her better connoisseurship than many of her male contemporaries. She and Charles were early champions of the so-called "Italian primitives." Lady Eastlake possessed a "readiness to appreciate, what was, at any given time, generally considered to be somewhat beyond the average range of approval." (Haskell). She was, characteristic of many nineteenth-century wealthy tastemakers, a contraction. Though she opposed compulsory elementary education, she supported women's suffrage. Though highly religious, she doubted Ruskin's (and other's) claims that art represented an age's moral values.