Maharaja Sir Yadavindra Singh, Mahendra Bahadur, Yadu Vansha Vatans Bhatti Kul Bushan, Maharaja of Patiala, GCIE, GBE (17 January 1913, Patiala – 17 June 1974, The Hague), Maharaja of Patiala from 1938 to 1974. He was the son and heir of Maharaja Bhupinder Singh, who he succeeded when he was only twenty-five. He had two wives, two children, was a noted horticulturist - later serving as chairman of the Indian Horticulture Development Council - and was a first-class cricketer who played in a Test match in 1934. He was also a much respected figure among his princely contemporaries - and a physically impressive one; he stood about six feet five inches tall. He served in Malaya, Italy, and Burma during World War II and, at Independence, he was influential in persuading other princely rulers to join the Indian Union. He served as president of the Indian Olympic Committee from 1938 to 1960, as Indian delegate to the United Nations General Assembly from 1956 to 1957, and to UNESCO in 1958. He later served as Indian Ambassador to Italy from 1965 to 1966 and as Indian Ambassador to the Netherlands from 1971 until his sudden death of heart failure at the age of sixty-one. On the orders of Prime Minister Indira Gandhi, the Maharaja of Patiala was cremated with full state honors.
(I haven't been able to definitely identify exactly when these images of the Maharaja were taken. But they seem likely to be from the time of his accession in 1938.)
One of the many jewels worn by the Maharaja in these images is the famous Patiala necklace created by the house of Cartier. Between 1925 and 1928, on the orders of his father, Maharaja Bhupinder Singh, most of the crown jewels of Patiala were redesigned by the firm; it was their single largest commission by any client. The finished necklace incorporated some 2,930 diamonds, including the world's seventh largest diamond, the 234.69 carat "De Beers", along with seven other diamonds which ranged from 18 to 73 carats, and a few Burmese rubies. Twenty years after its completion, this amazing item seems to have disappeared. The likely story is that, over time, the more important stones were removed and sold. Eventually, the "De Beers" reappeared and was sold in 1982 for over three million dollars. The remains of the original setting were found in London in 1998, and Cartier purchased the very incomplete necklace and spent four years restoring it. The missing stones have been replaced with carefully chosen copies.