On Tuesday, September 29, the two oldest people ever are going to square off in a debate as candidates for President of the United States of American.

Before Donald Trump, Ronald Reagan was the only person to pass his 70th birthday before being inaugurated as president, and at that, it was Reagan’s re-election (he first took office 17 days before his 70th birthday, in 1981). But now, we’re looking at an election in which whoever wins (ignoring the chance of a third-party candidate winning),

we’ll be inaugurating the oldest person ever to take the oath of office. On Inauguration Day 2021, Donald Trump will be 74 years 220 days old. That same day, Joe Biden will be 78 years 61 days old. And yes, Reagan is—at the moment—still the oldest president ever, having retired at the age of 77 years 348 days.

And the combined ages of the major party candidates so far outstrips any other election that it’s truly remarkable. Before 2020, the oldest combined ages of a two-candidate race was… well, in 2016, when 70-year-old Donald Trump defeated 69-year-old Hillary Clinton. But before that, we have to go back to 1984, when 73-year-old Reagan defeated 57-year-old Walter Mondale, and 1848, when 64-year-old Zachary Taylor (who died in office) defeated 66-year-old Lewis Cass.

In fact, the only candidates who’ve run for the presidency in their seventies were Trump, Reagan, Bob Dole (who lost the election of 1996 at the age of 73), and John McCain (who lost the election of 2008 at the age of 72). That’s it. Out of 57 elections, more than 75 major party candidates, and only four (now five) candidates more than 70 years old.

At the other end of the scale, everyone remembers that John Kennedy was the youngest president to be elected (he took office at the age of 43 in 1960), and all you trivia mavens also remember to correct that record, because Theodore Roosevelt succeeded to the presidency at the age of 42, upon William McKinley’s death in 1901.

But how many of you remember that the youngest major party candidate was actually 36 years old? Had William Jennings Bryan won the election of 1896 (the first of three in which he was the Democratic nominee), he would have taken office 15 days before his 37th birthday (he was born March 19, 1860). Instead, he lost to William McKinley, who was born January 29, 1843, and took office 34 days after his 54th birthday. (McKinley won the popular vote, 51.0% to 46.7%, and the electoral vote, 271 to 176.) So the election of 1896 was the youngest campaign in history. Bryan went on to run again in 1900, again losing to McKinley, and then suffering a further defeat, against William Howard Taft in 1908. Bryan died at the age of 65, in 1925.

The second youngest candidate was West Point graduate George B. McClellan, who was the commanding general of the Union Army early in the Civil War, and governor of New Jersey from 1878 to 1881. But when he lost to Abraham Lincoln’s re-election campaign of 1864, he was only 38 years old (he was born December 3, 1826). McClellan died at the age of 58, in late 1885.

The youngest campaigns were the elections of 1896, 1960, and 1860. In 1896, as I said, 54-year-old William McKinley defeated 36-year-old William Jennings Bryan. In 1960, it was the youngster John Kennedy defeating Vice President Richard Nixon, who was four years older than Kennedy.

On March 4, 1861 (Inauguration Day was March 4th, until the 20th Amendment changed it to January 20th, effective in 1937), Abraham Lincoln was 22 days past his 52nd birthday. In the election of 1860, he had defeated Vice President John C. Breckinridge (and also 64-year-old John Bell and 47-year-old Stephen Douglas—all four received electoral votes).

Breckinridge accomplished a great deal very early in life. Born January 16, 1821, he represented Kentucky in the House of Representatives from 1851 to 1855. In 1855, President Franklin Pierce appointed Breckinridge US Minister to Spain (and the Senate confirmed him), but he declined the appointment, and returned home to resume his law practice. In 1856, he was elected the youngest Vice President in US history, on James Buchanan’s ticket (he took office just after his 36th birthday). He lost the election of 1860 to Lincoln, but was elected to the Senate at the same time. He took his seat on March 4, 1861, but that summer, Kentucky seceded from the Union, and Breckinridge went with it. He was declared a traitor and expelled from the Senate on December 4, 1861. He served as a general in the Confederate army, and was the fifth (and final) Secretary of War of the Confederacy for a few months in 1865. After the war, he went into exile in Europe and Canada, and returned home in 1869, following President Johnson’s proclamation of amnesty. He died May 17, 1875.

The second youngest vice president to take office was Richard Nixon (he celebrated his 40th birthday 11 days before taking the oath of office). After serving two terms as Dwight Eisenhower’s vice president, Nixon lost the very close presidential election to John Kennedy in 1960, and then became the only former vice president to be elected president in 1968 (and the only president to resign, in 1974).

The Five Oldest Presidents

Considered by age at inauguration, the list runs as follows:

1. Donald Trump was 70 years 220 days old when he was inaugurated on January 20, 2017. If Joe Biden wins this year’s election, he will break that record at the age of 78 years 61 days.

2. Ronald Reagan was 17 days shy of his 70th birthday when he was inaugurated on January 20, 1989, and 17 days shy of his 78th birthday when he retired eight years later.

3. William Henry Harrison was 68 years 23 days old when he was inaugurated on March 4, 1841. The president who served the shortest term (31 days), he was the first to die in office, so he was only 68 years 54 days old when he left office.

4. James Buchanan was 65 years 315 days old when he was inaugurated in 1857, and 69 years 315 days old when he retired from office.

5. George H.W. Bush was 64 years 222 days old when he succeeded Reagan, in 1989, and 68 years 222 days old when he left office.

Considering age at the time the President left office, Dwight David Eisenhower moves into third place. He was only 62 years 98 days old when he was inaugurated in 1953, putting him seventh on the list, but serving two full terms (he and Reagan are the only two on this list to have served eight years as president), he was 70 years 98 days old when he retired.

The Five Youngest Presidents:

Article II, Section 1 of the Constitution requires a president to be at least 35 years old.

1. Theodore Roosevelt. Born on October 27, 1858, he was 42 years 322 days old when he was inaugurated on September 14, 1901, after William McKinley was assassinated. To beat Roosevelt’s record as the youngest president in the election of 2024, the newly elected president will have to have been born after March 4, 1982.

2. John F. Kennedy. Born on May 29, 1917, he was 43 years 236 days old when he took the oath of office on January 20, 1961, after winning the election of 1960. To beat Kennedy’s record as the youngest president elected, the winner of the election of 2008 will have to have been born after May 29, 1981.

3. Bill Clinton. Born on August 19, 1946, he was 46 years 154 days old when he was inaugurated on January 20, 1993.

4. Ulysses S. Grant. Born on April 27, 1822, he was 46 years 311 days old when he was inaugurated on March 4, 1869.

5. Barack Obama. Born August 4, 1961, he was 47 years 169 days old when he was inaugurated on January 20, 2009.

In order to join this list (and knock Obama off), the president who wins the election of 2024 will have to have been born after August 4, 1977.