|Tutankhamun's burial mask - |
one of the best known images from ancient Egypt
Reports of exactly what happened (and when) vary but most seem to agree that although the damage has only just been widely noticed, it was actually caused in August 2014 during routine maintenance - possibly to fix a lightbulb in the case above the mask.
The beard was made separately from the rest of the mask with enough time and the right conservation methods applied, this problem could have been fixed and the world would not have been any wiser. However, the job was rushed overnight (presumably so as to avoid reporting the problem) and rather than specialist glue, standard epoxy resin appears to have been used.
The problem with epoxy is that it is an extremely effective glue which means that if it is used incorrectly the effects are near irreversible. According to an unnamed staff member, not only is the glue visible along the top of the beard but some of the glue has dried on the mask's face and one of the 'repairers' left scratches on the mask when using a spatula to try to remove the glue...
Sources: The BBC, Live Science and The Guardian. The BBC report includes a photograph which may document the crucial moment when the mask was broken.