Analysis of English Long and Difficult Sentences

Although its historical mystery obviously cannot be solved in the adverbial clause, it fully proves that this book has a great influence on the exercise of attributes (from the earliest times and surprising social background adverbials).

Translation:

Although its historical mystery can't be solved obviously, a great deal of evidence shows that this book has had a great influence in surprisingly different social backgrounds since the earliest times.

(Translation: From Youdao)