Unknown Soldier from World War I being taken from the USS Olympia at the Washington Navy Yard and transported to the Capitol to lay in state (DC Public Library Commons)

Former president Wilson and recently inaugurated Harding attending the burial ceremony of the Unknown Soldier. President Wilson was instrumental in honoring those “unknown but to God” by having them interred in the Tomb of the Unknowns at Arlington National Cemetery.

Evening Public Ledger – Friday, November 11th, 1921

The ceremony made all the national and local evening papers that day. Above is Philadelphia’s Evening Public Ledger (for only 2 cents) from November 11th, 1921.

Ready for the start to Arlington – Unknown Soldier

Here’s something [found] on the Woodrow Wilson House website (if you haven’t visited, you should):

On his last official day in office, March 4, 1921, Woodrow Wilson also set into motion another of our Veterans Day traditions, the honoring of those fallen in battle “unknown but to God.” As Wilson arrived at the Capitol for the inauguration of his successor, Warren G. Harding, he went to the President’s Room in the Senate and signed the legislation that designated the interment of the remains of an Unknown Soldier at Arlington Cemetery. Later that day, Wilson moved to his new home at 2340 S Street in Washington, which is now the Woodrow Wilson House. On November 11, 1921, former President Wilson attended the ceremonies in the Rotunda of the Capitol for the Unknown Soldier and later that day he returned to his home to greet the crowd that had gathered there.

Crowds of people gathered for the interment of the remains of the Unknown Soldier

Read more here