Moving from Ireland to Berlin: Paperwork questions

Hi, my husband and I recently moved from Dublin to Berlin. We're in the process of filling out paperwork for public health insurance and we are being asked to submit proof that we were entitled to/had public health coverage in Ireland. Apparently saying "everyone has it/is covered" isn't good enough. Does anyone know how to provide proof that we are/were entitled to the HSE? I know the NHS has a card but does the HSE have anything similar? Thanks!