Today is King Chulalongkorn Day in Thailand, a celebration of the king also called Rama V. King Chulalongkorn (r. 1853-1910) was instrumental in modernizing Siam and fending off the European colonial powers. He outlawed slavery, and introduced the telegraph and railroads into his country.
King Chulalongkorn was also the grandfather of Thailand's current monarch, King Bhumibol Adulyadej. October 23 is the anniversary of his death in 1910.
King Chulalongkorn in 1901. Photo from Hulton Archive / Getty Images.