The archeological work in Šipka was conducted from 1879 to 1893 by Karel Jaroslav Maška. The cave was probably alternatively inhabited by Neandertals and cave bears. The site also yielded Mousterian tools and traces of hearths. This was the first discovery of Neanderthal remains in their cultural context.
References
^Jiří Svoboda, Vojen Ložek, Emanuel Vlček, "Hunters between East and West: the Paleolithic of Moravia", 1996, ISBN0-306-45250-2, pp.52-54 (Google books)