Thousands of people will stream through the Capitol rotunda this week to pay last respects to former President George H. W. Bush. You might think it's a tradition as old as our country, but you'd be wrong. This is only the 34th time in 156 years the ritual has been observed.

It all started with Henry Clay. The Kentucky statesman remembered for saying he would rather be right than president had served in the House (including being the only person ever elected speaker on his first day in office) and Senate and had been secretary of state and the Whig Party's presidential nominee three times. When he died at age 75 in his room in Washington's National Hotel, congressional leaders felt “Harry of the West” deserved a big sendoff.

Funeral services were held in the Senate chamber. Afterward, his casket was moved to the rotunda where, according to one account, a “vast multitude assembled” to view “all that remains of Henry Clay.”

And so a national tradition was born.

Thirteen years would pass before people returned to Capitol Hill to say farewell to another leader.

At 3 p.m. on Thursday, April 19, 1865 soldiers carried Abraham Lincoln's coffin up the Capitol's east steps (where he had delivered his Second Inaugural Address just seven weeks before). They placed it beneath the dome on a newly built structure that would soon become an American heirloom. It consisted of plain pine boards nailed together and covered in blackest broadcloth, an elegantly simple platform for holding a casket. It was transformed that day into the Lincoln Catafalque.

A brief, simple funeral service was held. Soldiers stood guard overnight. The public was allowed to walk past the casket the next day. One reporter counted 3,500 people an hour passing the remains for a total of 40,000 mourners. (“The number probably would have been twice as many” if the weather had been nicer, one newspaper opined.)

A total of 36 people have received the tribute over the years. (On two occasions, two individuals were honored at the same time: the Unknown Soldiers of World War II and the Korean conflict, plus the two victims of the 1998 Capitol shooting.)

It's worth noting that only presidents, military commanders, and members of Congress officially “lie in state.” Others, such as Rosa Parks, the Rev. Billy Graham, and two United States Capitol Police officers killed in the line of duty “lie in honor.”

The process isn't automatic, either. It takes a congressional resolution or the approval of congressional leadership to happen. Even then, the deceased's family must agree to it. While all four assassinated presidents (Lincoln, Garfield, McKinley, and Kennedy) have lain in state, other presidents' families were split on it. Those of Hoover, Eisenhower, Johnson, Reagan, Ford and now George H. W. Bush opted for the tribute, while the families of Franklin Roosevelt, Truman, and Nixon declined.

The practice is growing more common. In 2018 alone, three Americans (Billy Graham, Sen. John McCain, and President Bush) have lain in state or honor, the most ever in a single year.

Most honorees share one thing in common. Since 1865, almost all caskets have rested on the Lincoln Catafalque. Its black material has been replaced several times over the years and its size expanded to accommodate larger, modern caskets. But the same simple boards hammered together for Lincoln remain in place today, holding the remains of men and women who made important contributions to the American story.

So we repeat the custom in our time of grief. The country collectively sheds tears and whispers “thank you” via our fellow citizens filing past the casket. In a nation whose government is of the people, by the people, and for the people, there can be no more fitting tribute than that.

J. Mark Powell (@JMarkPowell) is a contributor to the Washington Examiner's Beltway Confidential blog. He is a former broadcast journalist and government communicator. His weekly offbeat look at our forgotten past, "Holy Cow! History," can be read at jmarkpowell.com.