Famous scientists A.T. Fomenko and G.V. Nosovsky, in a popular book intended for a wide range of readers, talks about their research on the chronology of ancient and medieval history, which led to the creation of a new chronology, significantly different from the generally accepted version of Scaliger - Petavius. The book criticizes the traditional version of the history of Rus', China, England, and proposes a new version of the history of these countries, consistent with both the new chronology and the numerous evidence of old documents. A general scheme is given for the tentative reconstruction of history from the 10th to the 17th centuries AD. e. The calendar and astronomical basis of the dating of the Nativity of Christ and the First Ecumenical Council in Nicaea, accepted today, is analyzed. The fallacy of both of these datings is shown and new, corrected dates are given: 1095 AD. e. for the crucifixion of Christ and the era of the VIII–XIII centuries AD. e. for the Council of Nicaea.