At 92 years and 10 months old, Mahathir Mohamad has become the oldest serving world leader after being sworn in as prime minister of Malaysia for a second spell.
Mahathir was previously PM between 1981 and 2003, and he joins a select band of world leaders who are in power in their 80s or above. His country became independent 60 years ago, when he was 32.
The world’s oldest leaders – in their 90s
Queen Elizabeth II, at 92 years old, was the oldest world leader before Mahathir was re-elected. Her 96-year-old husband has withdrawn from public duties but no retirement date has been set for Her Majesty.
Just a little younger than the Queen, at 91, is Beji Caid Essebsi, the president of Tunisia. He took office in 2014 after he was persuaded to come out of retirement to stand as a candidate in Tunisia’s first free presidential election since independence from France.
Another nonagenarian on the world stage is North Korea’s Kim Yong-nam, 90, who has been chairman of the Presidium of the Supreme People’s Assembly since 1998. He became the highest-level official from North Korea to visit the South this year, during the rapprochement that led to a unified team appearing at the Pyeongchang Winter Olympics.
Rocking along in their 80s
At 88, Sheikh Sabah al-Ahmad Al Sabah has a couple of years to go to before he can join the elite club of rulers in their 90s. He has been emir of Kuwait since 2006.
Dame Marguerite Pindling, the governor general of the Bahamas, is a few weeks away from turning 86. And 85-year-old Sir Colville Young has been the governor general of Belize for 25 years.
Paul Biya, also 85, has been the president of Cameroon since 1982. In a country that appears to favour experience over youth, the prime minister, Philémon Yang, is a comparative spring chicken at 70.
Emperor Akihito of Japan, now 84, inherited the Chrysanthemum throne in 1990. It has been announced that he will abdicate on 30 April 2019.
In the Middle East, two near neighbours have similarly aged elder statesmen at the top. Michel Aoun, 83, is president of Lebanon, while Mahmoud Abbas, 83, is president of the Palestinian Authority.
Older than 100 but not in power any more
There are two living former world leaders over the age of 100. Do Muoi, who was general secretary of the central committee of the Communist party of Vietnam during the 1990s, is now 101. Babiker Awadalla, who was briefly prime minister of Sudan in 1969, is believed to be still alive and also 101.
… and the youngest
At the other end of the scale, there are a handful of world leaders under the age of 40, and not all of those are because of the hereditary principle that can sometimes deliver very young rulers. (In 1945, Fuad II became Egypt’s head of state for 11 months, “taking charge” when he was just 192 days old.)
Matteo Ciacci, 28, one of the Captain Regents of San Marino, was the first person born after the fall of the Berlin Wall to become a head of state. The Republic of San Marino has dual heads of state, in an echo of the dual authority wielded by the consuls of ancient Rome. Ciacci was elected last month and will serve a six-month term.
A little older are Austria’s chancellor, Sebastian Kurz, 31, North Korea’s Kim Jong-un, 35, and New Zealand’s Jacinda Ardern, 37.