From recent research and information accumulated over the last 2 centuries, the history and actual state of preservation and restoration of 8 great altar reredos with carved figures in the shrine, coronation scene, reliefs, and paintings in the aisles, is briefly reviewed. Following the program of the Austrian Bundesdenkmalamt (Federal Bureau of Monuments) of the last years, now the 11 meter-high altar at Hallstatt (1515-1520) has been preserved and documented technically and historically. The results include wooden structures and construction techniques, polychromies with rich gildings and glazings, paintings combining oil techniques with tempera highlights. In parts the overpaintings from 1894-1895 had to be left. -- AATA