The circumcision booklets of Amsterdam were written in Hebrew, and are generally of good reading quality. The number of remaining booklets is very low. About 100 booklets could be retrieved and they form part of the collection of Death, Marriage and Burial indexes at the Municipal Archive of Amsterdam (Stadsarchief Amsterdam). As the booklets were written by the circumcisers themselves, one notices that not all circumcisers had the same knowledge of the Hebrew language and that some of them were dyslexic. Since no birth records are known to be kept by the Jewish community before 1785, the circumcision booklets are the only proof of the birth of Jewish boys in Amsterdam up to that year. In 1785, the city government ordered the births of children to be registered.