The Working Group Historical Instruments (WG-HI) was founded by the members of Commission 41 at the 2000 Manchester IAU XXIV General Assembly, with the main objectives to assemble a bibliography of existing publications relating to such instruments, and to encourage colleagues to carry out research and publish their results. Membership of the WG-HI has increased from three to nine people since its foundation. This clearly demonstrates the IAU members increasing interest in safeguarding old astronomical instruments and buildings as witness to their own country's cultural heritage and scientific progress.