President-elect Donald Trump’s return to the White House will coincide with Martin Luther King Jr. Day a rare event.

Between Martin Luther King Jr. Day being a relatively new holiday (it was made a federal holiday in 1983) and inaugurations only happening every four years, the two events have only lined up once before.

And it will be more than two decades before it happens again. The next time Martin Luther King Jr. Day falls on Jan. 20 during an inauguration year will be the 2053 Inauguration Day for the 2052 Presidential Election.

Here’s what to know:

Has a president ever been inaugurated on Martin Luther King Jr. Day before?

A limited number of presidents have had their Inauguration Days held on Jan. 20 – 14 out of 46 – and even fewer have had the honor line up with Martin Luther King Jr. Day.

Since the holiday was officially designated in 1983, only one president was sworn in on Martin Luther King Jr. Day: former President Bill Clinton. For his second term, Clinton’s Inauguration took place on Jan. 20, 1997.

Two other presidents had inaugurations on Monday, January 20, but they were held before Martin Luther King Jr. Day was a holiday. Franklin D. Roosevelt was sworn in for his third term on Monday, Jan. 20, 1941, and Richard Nixon was sworn in for his first term on Monday, Jan. 20, 1969.

Barack Obama’s second Inauguration Day

Barack Obama can also be counted as having a half-Martin Luther King Jr. Day Inauguration. For his second term Inauguration, Jan. 20 was on a Sunday, so there was a private ceremony held on Sunday where he was sworn in and a public ceremony the following day which was Monday, Jan. 21, 2013, and that just so happened to be Martin Luther King Jr. Day that year.

So, while he started his second term on Sunday, Jan. 20, his public ceremony was held on Martin Luther King Jr. Day.

Has Inauguration Day always been Jan. 20?

Inauguration Day was not initially held on Jan. 20. When George Washington was first sworn in as president, Congress made it so that the first Wednesday in March would be the day of Inauguration. In 1789, this would have been Wednesday, March 4. While this didn’t end up happening because of logistical delays, they decided to change it to where future inaugurations would be held on March 4 in honor of what was supposed to be the first Inauguration Day.After that, the tradition stood for over 100 years with exceptions for years when March 4 fell on a Sunday. The change for Inauguration Day didn’t come about until 1922 when Nebraska Senator George Norris introduced what would become the Twentieth Amendment. Norris proposed to shorten the period between the election and inauguration of the next president as communication and travel methods had gotten better in the 20th century, and there was no need to have the former president making decisions for an extra four months.

The amendment passed in 1932 and ratified by the states in 1933. Franklin D. Roosevelt was the first president sworn in on January 20 when the Inauguration for his second term took place in 1937.