When the family moved to London in 1841 she began researching in the British Museum and elsewhere, and during the 1840s she worked on "Letters of Royal and Illustrious Ladies" (1846) and "Lives of the Princesses of England: from the Norman Conquest " (1849–1855). She had started work on this book in 1843, using private libraries like that of the rich collector Sir Thomas Phillipps, as well as archives like those at Lambeth Palace. After her marriage to the painter George Pycock Green in 1845, they travelled for the sake of his artistic career, and she was able to research her subject further in Paris and Antwerp. "Lives of the Princesses" was praised by the antiquary Dawson Turner and by the historian Sir Francis Palgrave among others.