York City, printed numerous lists of Jewish Holocaust survivors located in Europe, from September 1944 until 1946. Over time, many Holocaust survivor registries were established. Initially these were paper records, but from the 1990s, an increasing number of the records have been digitized and made available online. Hidden children Following the war, Jewish parents often spent months and years searching for the children they had sent into hiding. In fortunate cases, they found their children were still with the original rescuer. Many, however, had to resort to notices in newspapers, tracing services, and survivor registries in the hope of finding their children. These searches frequently ended in heartbreak — parents discovered that their child had been killed or had gone missing and could not be found. For hidden children, thousands who had been concealed with non-Jews were now orphans and no surviving family members remained alive to retrieve them. For children who had been hidden to escape the Nazis, more was often at stake than simply finding or being found by relatives. Those who had been very young when they were placed into hiding did not remember their biological parents or their Jewish origins and the only family that they had known was that of their rescuers. When they were found by relatives or Jewish organizations, they were usually afraid, and resistant to leave the only caregivers they remembered. Many had to struggle to rediscover their real identities. In some instances, rescuers refused to give up hidden children, particularly in cases where they were orphans, did not remember their identities, or had been baptized and sheltered in Christian institutions. Jewish organizations and relatives had to struggle to recover these children, including custody battles in the courts. For example, the Finaly Affair only ended in 1953, when the two young Finaly brothers, orphaned survivors in the custody of the Catholic Church in Grenoble, France, were handed over to the guardianship of their aunt, after intensive efforts to secure their return to their family. In the twenty first century, the development of DNA testing for genealogical purposes has sometimes provided essential information to people trying to find relatives from whom they were separated during the Holocaust, or to recover their Jewish identity, especially Jewish children who were hidden or adopted by non-Jewish families during the war. Immigration and absorption After the war, anti-Jewish violence occurred in several central and Eastern European countries,