Henry had built the "Domus Conversorum" in London in 1232 to help convert Jews to Christianity, and efforts intensified after 1239. As many as 10 percent of the Jews in England had been converted by the late 1250s in large part due to their deteriorating economic conditions. Many anti-Jewish stories involving tales of child sacrifice circulated in the 1230s–50s, including the account of "Little Saint Hugh of Lincoln" in 1255. The event is considered particularly significant, as the first such accusation endorsed by the Crown. Henry intervened to order the execution of Copin, who had confessed to the murder in return for his life, and removed 91 Jews to the Tower of London. 18 were executed, and their property expropriated by the Crown. At the time, the Jews were mortgaged to Richard of Cornwall, who intervened to release the Jews that were not executed, probably also with the backing of Dominican or Franciscan friars.