This view from the southeast of the Royal Monastery of Tan-gye-ling (also seen as Tangia Ling, Tangye-ling, or Tan gye Ling in other sources) is from a collection of 50 photographs of central Tibet acquired in 1904 from the Imperial Russian Geographical Society in Saint Petersburg by the American Geographical Society. Tan-gye-ling was the monastic palace of Demu-khutuktu (also known as Demohutuktu), the late regent. In the distance are the “iron mountain,” Ch'agpori (also Chagpori, Chiakpori, Chapori, Chakpori, Chaga, or Chag-pa hill) on the left and the Dalai Lama’s palace, Potala, on the right. Tan-gye-ling is on the second plane. The flat-roofed building in the foreground is a private house. On the far left is a group of Dar-cog, or prayer flags (also seen as Da-cha, dar-lch'og, or Dar Cho). According to L.A. Waddell, in the 1899 edition of The Buddhism of Tibet or Lamaism: "A regent is necessary to conduct the temporal government, especially under the system of papal succession by re-births, where the new Dalai Lama does not reach his majority and nominal succession to temporal rule till his eighteenth year. In order to avoid plotting against hierarchies, Nag-wan ruled that the regent must be a Lama, and he restricted this office to the head Lamas of the monastic palaces or Ling of Lhasa, named Tan-gye-ling, Kun-de-ling, Ts'ech'og-ling, and Ts'amo-ling." The photographs in this collection were taken by two Mongolian Buddhist lamas, G.Ts. Tsybikov and Ovshe (O.M.) Norzunov, who visited Tibet in 1900 and 1901. Accompanying the photos is a set of notes written in Russian for the Imperial Russian Geographical Society by Tsybikov, Norzunov, and other Mongolians familiar with central Tibet. Alexander Grigoriev, corresponding member of the American Geographical Society, translated the notes from Russian into English in April 1904.