Antique print of the Sultan of Yogyakarta taken from a book published in 1880.

Based on the provenance, this man is either Sultan Hamengkubuwono VI or Sultan Hamengkubuwono VII. If it is the contemporaneous sultan, then it would be Sultan Hamengkubuwono VII. The 7th Sultan of Yogyakarta was the longest reigning monarch of Indonesia in the 19th century. He was also a moderniser and a lover of photography, such that he educated the first native photographer of Indonesia, Kassian Céphas, so he could have a private photography studio in his palace.