Ronald Reagan started a tradition as he prepared to leave office after two terms as president: Write a note congratulating your successor and leave it in the Oval Office desk drawer.

Ronald Reagan scribbled a note in 1989 to his successor above an elephant cartoon. The tradition, started perhaps inadvertently, was continued by Joe Biden.

As President Joe Biden prepared to pass the baton to President-elect Donald Trump, he followed the tradition of leaving his successor a note.

Monday’s change of Oval Office occupants is a ritual full of traditions and customs. One of the more modern ones began in 1989, when Ronald Reagan left a note for George H.W. Bush on stationery with a whimsical bit of advice.