This book contains two manuscript texts of Ferdinand Verbiest, S.J. (1623 - 1688), written in 1676 in Beijing to the attention of the Russian tsar, and brought by the legate Nicolas Spathary Milescu to Moscow. Both texts represent the oldest layer of the Astronomia Europaea corpus, and were until recently forgotten. Their recent discovery was in the form of a manuscript copy, which Chysanthos Notaras had made them in Moscow in 1693. The manuscripts have since then been kept in library of the Metochion of the patriarchate of Jerusalem in Constantinople. In this publication, the authors are reconstituting the Latin text, translating it in English and annotating it. In the Introduction, the manuscripts are situated within the corpus of Verbiest’s Latin writings, and are depicted both the parts that were afterwards re-cycled in the well-known Compendium Latinum and Astronomia Europaea edition (Dilingen, 1687), and those that were eventually omitted. Moreover, the story of the Moscow manuscript, and especially that of its Constantinopolitan copy - until now the only remaining testimonium of it - is traced. This description also reveals an until now unknown reception of 17th century Jesuit astronomy, mechanics and physics in post-Byzantine Russia and South-Eastern Europe.