A team of researchers led by Nottingham Trent University’s Imaging and Sensing for Archaeology, Art History and Conservation (ISAAC) lab have discovered evidence of a mistake made more than 700 years ago while investigating the painted Buddhist temples in the Mogao Caves, a UNESCO World Heritage Site on edge of the Gobi Desert, in Dunhuang, China.
The researchers used a variety of non-invasive imaging techniques to analyse the wall paintings, because of their fragile nature and the high ceilings in the cave. These techniques allowed them to study the paintings from the ground and made it possible to identify colour pigments and discern faded writing that would not be visible otherwise. The results of this research are reported in a paper in Scientific Reports (https://doi.org/10.1038/s41598-020-76457-9).
The surprising discovery was made in Cave 465, which is decorated in a unique Indo-Tibetan tantric Buddhist style, with a painting of the Five Celestial Buddhas on the ceiling. At the foot of each Buddha is a piece of identical Sanskrit writing: a phrase known as the ‘Summary of Dependent Organisation’, which presents a precis of Buddha’s teachings. Each piece of text would have been printed on to a piece of paper in cinnabar (a red pigment) and this would then have been glued to the ceiling as part of the consecration ritual. However, it was revealed that one of the sheets of paper on the west ceiling had been glued face down, so that the letters were flipped and the writing was barely visible – perhaps the workman applying it did not understand Sanskrit and failed to notice that all the letters were the wrong way round.
The research also shed light on the date of the paintings in Cave 465, which, like many of the Mogao Cave temples, has long been the subject of debate. The possible date range suggested covered more than five centuries and three different empires, from 9th-century Tibetan through 11th- to 13th-century Tangut to 13th- to 14th-century Mongol/Yuan. By palaeographic study of the script, certain letters were identified that were written in a style used only after the late 12th century. Analysis of the pigment combinations used in the paint, which correspond best with the Mongol/Yuan period, confirmed the conclusion that Cave 465’s paintings date from the late 12th to 13th century.