During his visit to Jerusalem in 1898 for the dedication of the Protestant Church of the Redeemer, Kaiser Wilhelm II bought this piece of land on Mount Zion for 120,000 German Goldmark from Sultan Abdul Hamid II and presented it to the “German Union of the Holy Land” (“Deutscher Verein vom Heiligen Lande”). According to local tradition, it was on this spot, near the site of the Last Supper, that the Blessed Virgin Mary died. In Orthodoxy and Catholicism, as in the language of scripture, death is often called a “sleeping” or “falling asleep”. This gave the original monasteryits name; the church itself is called, as it has always been, the Basilica of the Assumption (or Dormition).
The architect and buildings manager of the Diocese of Cologne Heinrich Renard (1868–1928) investigated the site in 1899 and discovered the remains of the Byzantine church of “Hagia Sion” and also of other churches. Connected with this is the thesis of Bargil Pixner of a pre-Crusader Church of Zion, Jerusalem. Direction of construction was entrusted to the architect Theodor Sandel, a member of the Temple Society and a resident of Jerusalem. The foundation stone was laid on 7 October 1900. Construction was completed in only ten years; the basilica was dedicated on 10 April 1910 by the Latin Patriarch of Jerusalem.
source : Wikipedia