In the Middle Ages, Jews who converted to Christianity occupied a shadowy and often dangerous place between the two religions. Rejected by their former community, and sometimes not accepted fully as Christians, converts were often destitute and at the mercy of noble benefactors. Only in London was there an official, royally sanctioned and funded, policy of conversion. When Henry III founded the Domus Conversorum, in 1232, he created a unique institution, one intended to house, protect, and instruct converts from Judaism. This book provides an analysis of Jewish conversion in England and continental Europe in the 12th and 13th centuries and offers a detailed look at London's Domus Conversorum: its finances, its administration, and its inhabitants. Using royal records, financial accounts and receipts, Church letters and documents, London wills and assizes, and chronicles, this book presents the most in depth account of Jewish conversion in London to date.