With no explanation, label text_A→text_B with either "DON'T KNOW", "NO" or "YES".
text_A: Doubravka died in 977. In his study of 1888, Józef Ignacy Kraszewski wrote that "her tomb was discovered in Gniezno Cathedral. It was a simple stone marked with a cross. Purple robes and a weighty gold loincloth were the only objects found in her tomb." A similar view of Doubravka's burial place was expressed earlier, in 1843, by Edward Raczyński in his study "Wspomnienia Wielkopolski to jest województw poznańskiego, kaliskiego i gnieźnieńskiego" (Memories of the Greater Poland districts of Poznań, Kalisz and Gniezno). However, the burial place of the Bohemian princess is now considered to be a mystery.
text_B: Is Doubravka a popular and well known Bohemian princess?
DON'T KNOW.