Under laboratory conditions samples being tested for their stability with changes of relative humidity, with the application of artificial aging, low-grade temperatures and biological agents, were prepared by impregnation with various synthetic polymers (VA 2 EGA, polyacrylamid, and K-42). After laboratory tests some experiments were carried on under natural conditions within an architectural monument. As a result, a complete working conservation program was developed and carried out in 1970-71 on the 17th century church of the Installation of the Cross in the city of Drogobych in the Lvov region. -- AATA