answer:There are three possible questions here: Who is the oldest living monarch at present? Queen Elizabeth b. 21 April 1926, succeeded 1952. She nudges out King Bhumibol of Thailand by five months. Who is the longest reining monarch at present? King Bhumibol of Thailand, succeeded in 1946, has reined for 70 years. Who was the longest reining monarch ever? King Subhuza of Swaziland, succeeded in 1899, died upon the throne, 1982. Reined for 82 years, 254 days.