The book presents the independent astronomical dating obtained by the authors for the writing of the famous biblical book Apocalypse. It is in the Apocalypse that the so-called “number of the beast 666” is spoken of. It turns out that the Apocalypse was written not in the first centuries of our era, as is usually believed, but in 1486 AD. e. In the light of the new dating of the Apocalypse and the general reconstruction of history proposed by the authors on the basis of the New Chronology, the situation in which the Apocalypse was written becomes clear. It was a time when all of Europe fearfully awaited the inevitable end of the world in 1492. Anxiety and gloomy feelings of anticipation of the end of the world were clearly manifested in the Apocalypse. In addition, the reader will learn what the notorious “number of the beast” 666 actually is. The true meaning of this apocalyptic number is exactly the opposite of what is usually put into it. The book does not require special knowledge and is intended for anyone interested in the use of mathematics for revealing the mysteries of our history.