Traces the conservation measures and renovations of the main altar in St. Mary's Church in Cracow, over a period of 500 years. The earliest documented work was repainting and gilding. The most extensive restoration was carried out in 1866-1871, under supervision of professors from Cracow School of Fine Arts; this work involved wood replacement and painting. The next major renovation was from 1946-1949 after the return of the altar from Nurnberg, where it had been taken by the Germans. Gilding was renewed, missing elements of the sculpture supplemented, the wood protected against insects with arsenic in alcohol, and a minium coating given to unpolychromed and ungilded parts. Damage to the cabinet, occurring when it was dismantled in 1940, has not yet been repaired.