Dubai - The picture shows an Emirati man wearing traditional clothes, sporting a a dagger and a long beard.
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Sharing the photo on her Instagram account, Sheikha Bodour said the picture was taken by a captain of naval ship in March 1866.
Sheikh Zayed bin Khalifa Al Nahyan - also known as Zayed the Great or Zayed the First -was the ruler of Abu Dhabi from 1855 until his death in 1909.
The photo captured Zayed the First at 31 years old, Sheikha Bodour said, adding that she found the picture in Sheikh Sultan's library.