Hemis Monastery existed before the 11th century.
In this manuscript Naropa (or Naro) meets the "dark blue" (Skr.: nila: dark blue or black) Tilopa (or Tillo), a tantric master, who gives Naropa 12 "great" and 12 "small" tasks to do in order to enlighten him to the inherent emptiness/illusoriness of all things.