Grutrissheit

Grutrissheit (グルトリスハイト, Gurutorisuhaito) is the name of Mestionora's bible. According to legend, it is the original bible that the first king of the country was permitted to transcribe upon being chosen by the Gods. Therefore, it is the symbol of power for all Zents.

Presumably all other Bibles have been derived from this transcription by the first king.

Spoiler from Part 4 Volume 7 In the ancient past, it was tradition for each Zent to make their own transcription directly from the first one that the first king had transcribed directly from Mestionora's bible. Over time however this changed to the successor copying their father's transcription, rather than the original Grutrissheit.

During the ravages of the last civil war, the bible written by the previous king was lost. In theory it is now the duty of the current Zent Trauerqual to make a new transcription from the original Grutrissheit of the first king, but unfortunately its location is currently unknown.

Ferdinand of Ehrenfest speculates in private that its location has been passed down from kings to successors only orally. Since the current king was originally raised as a vassal to his older brothers and only became king due to exceptional circumstances, he never received this knowledge, leaving him unable to fulfill this duty.