The views on Great Moravian sacral architecture changed dramatically during the second half of the 20th century. At first, researchers assumed it to be limited to simple wooden churches like those known from the German environment in dating from the 7th-8th century. These wooden churches were suitable for initial missionary activities due to the easy availability of materials, quick construction and no need for consecration. This opinion was refined in 1949 after excavations in Staré Město. From the 1960s, stone churches have also been excavated in Slovakia. As of 2014, more than 25 sacral buildings have been safely identified in the core territory of Great Moravia (Moravia and Western Slovakia). The remains of the first uncovered churches were only "negatives" (ditches filled with secondary material after removal of original foundations), but later research also uncovered remains of buildings with original foundations. Especially after the discovery of Great Moravian graves near the church in Kopčany, the potential Great Moravian origin of several still-standing churches in Slovakia ("viz.", Kopčany, Nitrianska Blatnica, Kostoľany pod Tribečom) was once more an open question. The exact dating is a goal of ongoing research based on radiocarbon analysis and dendrochronology.