In 1812, Judith Cohen married Moses Montefiore, a stockbroker who became a towering figure of the 19th-century international Jewish world. It was a notable event as the first major union between the Sephardic (Spanish/Italian) and Ashkenazi (Eastern European) Jewish families. Judith's sister, Hannah (Henriette) married Nathan Mayer Rothschild and the two brothers-in-law became business partners. The Montefiores, although observant Orthodox Jews, became one of the most influential couples in upper-class English society, which was then entirely Christian. Her book The Jewish Manual, or, Practical Information in Jewish and Modern Cookery, With a Collection of Valuable Recipes and Hints Relating to the Toilette, published in 1846, was the first Jewish cookbook and manual on personal hygiene and social deportment written in English. It reflected Lady Montefiore's extensive knowledge of the great French chefs of the era, their culinary techniques and terminology, to which she added material from her own family background and her experience from travel to Europe and the Middle East. The recipes, which can still be used today, provided an introduction to haute cuisine previously unknown to Polish and Russian Jews. In 1838, Moses Montefiore was knighted by Queen Victoria and Judith became Lady Montefiore. She served as a member of several charity boards, including the Jews' Orphan Society and the Ladies' Loan and Visiting Society. The Montefiores gave generously to Jewish causes in England and worldwide, and often interceded on behalf of needy or oppressed Jews in other nations. They helped establish the first Jewish farming settlements in Israel. Their country home at East Cliff Lodge in Ramsgate became a center of Jewish life in England. Sir Moses and Lady Montefiore kept diaries that were published in 1890.