On 26 February 1814 King William I decreed that the Nederlandsch Israëlitisch Seminarium (NIS) was to be established in Amsterdam to train rabbis, teachers and other officers serving the Jewish community.
Simon Heertjes, the son of Elie, attended the NIS.
In addition, Jokos files (numbers 55259, 55863) on this family or other family members are at the Amsterdam Municipal Archive. Access is subject to authorization from the Stichting Joods Maatschappelijk Werk.