The photo below was found in an envelope among a bundle of family photos which were recently handed down on the English side of my family.
Aside from the photo itself, the only clues are as follows:
The word 'Prince' is written on the back of the photo in pencil. This could be misleading but, given the next point below, that seems unlikely.
All of the other photos in the envelope containing the picture above which have been identified so far are of European royals (with one exception, a yet-to-be identified Maharajah). Among these are ones of Alfred, second son of Queen Victoria, and Grand Duchess Maria Alexandrovna of Russia.
Judging by the age of the people identified so far, most of the photos were probably originally taken between the late 1860s and the mid 1870s. If the 'Prince's' photo falls into this bracket, he would probably have been born in the mid 1850s or early 1860s.
The photos seem to have been collected either by my Great Grandmother (b. 1851) or my Great Great Grandmother (b. 1833).
I'd be grateful for any information or additional clues which might lead to an identification of the boy. A definite answer to the main question would be great, but I don't know if there is enough information here for that to be possible.