 Chmielowski compiled data from a few hundred references, dating from antiquity to his contemporary.Almost every sentence in the book is in-line referenced, frequently in Latin, a lingua franca in Poland among the educated classes as in most of Central and Western Europe of the 18th century.To the data from more than a hundred original authors, Chmielowski added personal annotations, for example, "Dragons existed for sure, I myself held, visiting Radziwills' castle, a rib of a dragon bigger than a regular sabre".