Thanksgiving is next Thursday, Nov. 27, but another tradition is typically celebrated at the White House just a few days before the holiday: the presidential turkey pardon.

President Donald Trump is expected to spare two ceremonial turkeys on Tuesday, Nov. 25. Meanwhile, the Office of the First Lady has taken to social media to encourage people to vote for their favorite names for this year's pardon recipients. The options are: Sugar and Spice, Pumpkin and Pie, Gobble and Waddle or Acorn and Squash. But which president was first to pardon a turkey – and how the ceremony evolved – remains a combination of lore and historical documents. Before you start planning your holiday dinner, here’s a refresher on the unusual annual event.

Beg your pardon? Why do Presidents pardon turkeys? We explain the tradition.

The tradition of a White House ceremony ahead of Thanksgiving began in 1947, when President Harry Truman received a live turkey from the National Turkey Federation, according to the National Archives. Contrary to reports that he pardoned the turkey, the Truman Library suggests the bird was probably served as dinner.

In recent years, the White House has selected which turkey should be presented as the National Thanksgiving Turkey and which should be the alternate, according to the organization. The president announces the final choice during the ceremony, but both are spared and sent to a petting zoo or an agricultural center for the remainder of their lives.