Since the beginning of the Iraq War in March 2003, yellow ribbons increasingly embellish the American landscape.

Tied around trees, decorating front porches and decals of them adorning vehicles of every shape and size, they symbolize Americans’ desire for the safe return of loved ones, and soldiers in general, serving in the military far away from home. Often accompanied by words like “we support our troops,” the phenomenon of displaying yellow ribbons more generally has come to convey a sense of national pride and patriotism.

Though now a popular phenomenon, the origins of this tradition are far from unambiguous. Many stories have been propagated through the years on how the practice was transformed into widespread American tradition. However, arguably no organization has studied this trend and its roots in more depth than the Library of Congress’s American Folklife Center, whose late employee of 21 years, Gerald E. Parsons, traced the yellow ribbon back to such disparate events in history as the arrival of a 1973 American hit song, the Iran hostage crisis and the Watergate scandal.

Parsons concluded that a practice similar to the current one originated from as early as the 1950s after he discovered a legend retold in a 1959 book, in which a man homeward bound after serving a five-year prison term had asked his family to tie white ribbons around an apple tree if they desired his return.

Throughout the 1960s, this tale of an ex-prisoner’s homecoming appears to have circulated among religious groups in print and oral tradition, both versions closely resembling the New Testament’s “Parable of the Prodigal Son.”

In October of 1971, Pete Hamill wrote “Going Home,” an article for the New York Post. The piece recounts a trip made by an ex-convict who is watching for a yellow handkerchief on a roadside oak. Hamill claimed to have heard this story in oral tradition. Soon after, it was made into a television movie, in which James Earl Jones played the ex-convict, Parsons wrote.

Almost a year later, Irwin Levine and Larry Russell Brown released a song they called “Tie a Yellow Ribbon Round the Ole Oak Tree.” Made famous in 1973 by popular vocal group Dawn, featuring Tony Orlando, the authors said they based the song on a story they heard while serving in the military.

According to Parsons, the tradition of displaying yellow ribbons for the return of an ex-prisoner was transformed into the country’s current expression of support for absent loved ones after the United States became entangled in the Iran hostage crisis of 1980-81. Penelope Laingen, wife of Bruce Laingen, U.S. charge d'affaires in Teheran who was among the hostages, appears to have sparked the practice nationwide after an article was published in December 1979 in the Washington Post about her husband’s plight and a yellow ribbon that she had tied to an oak tree in his memory. Ms. Laingen said she was inspired by Levine’s and Brown’s "Tie a Yellow Ribbon Round the Ole Oak Tree” and the prior example of one Gail Magruder.

Gail Magruder, wife of Jeb Stuart Magruder, who was convicted in the Watergate scandal, put yellow ribbons on her front porch to welcome her husband home from jail. This event was televised on the evening news.

Later, Laingen recalled: “It just came to me to give people something to do, rather than throw dog food at Iranians. I said, 'Why don't they tie a yellow ribbon around an old oak tree.' That's how it started.” Thus, Ms. Laingen stepped in to change the legend and song from the return of a forgiven prodigal to the return of an imprisoned hero.

Yellow ribbons resurfaced a decade later during the first Gulf War, reflecting the public’s collective longing for a heroic return of its soldiers.

Today, in addition to the ubiquitous yellow ribbon, Americans are used to seeing looped ribbons of various colors displayed on the lapels, jackets and dresses of all walks of life.

The Cincinnati Enquirer reported that this practice first gained popularity in the early 1990s when a number of New York artists linked to the nonprofit group Visual AIDS came up with the idea to create a red ribbon, according Visual AIDS executive director Amy Sadao. The symbol was used to represent compassion and solidarity for people living with the disease and their caregivers, while the color red symbolized passion, blood and love, said Sadao. Later, the trend gained momentum after actor Jeremy Irons appeared on the nationally televised Tony Awards in 1991 wearing the ribbon, according to the Enquirer.

Since the appearance of the red AIDS ribbon, many others have emerged. For example, the Breast Cancer Research Foundation had a pink ribbon designed to bring about more awareness of the breast cancer. Similarly fashioned red, white and blue ribbons appeared immediately following the terrorist attacks of September 11, 2001.